The OM1 segment contains the attributes that apply to the definition of most observations. This segment also contains the field attributes that specify what additional segments might also be defined for this observation.
Figure 8-7. OM1 attributes
SEQ |
LEN |
DT |
OPT |
RP/# |
TBL# |
ITEM# |
ELEMENT NAME |
1 |
4 |
NM |
R |
00586 |
Sequence Number |
||
2 |
200 |
CE |
R |
00587 |
Producer's Test/Observation ID |
||
3 |
12 |
ID |
O |
Y |
0125 |
00588 |
Permitted Data Types |
4 |
1 |
ID |
R |
0136 |
00589 |
Specimen Required |
|
5 |
200 |
CE |
R |
00590 |
Producer ID |
||
6 |
200 |
TX |
O |
00591 |
Observation Description |
||
7 |
200 |
CE |
O |
00592 |
Other Test/Observation IDs for the Observation |
||
8 |
200 |
ST |
R |
Y |
00593 |
Other Names |
|
9 |
30 |
ST |
O |
00594 |
Preferred Report Name for the Observation |
||
10 |
8 |
ST |
O |
00595 |
Preferred Short Name or Mnemonic for Observation |
||
11 |
200 |
ST |
O |
00596 |
Preferred Long Name for the Observation |
||
12 |
1 |
ID |
O |
0136 |
00597 |
Orderability |
|
13 |
60 |
CE |
O |
Y |
00598 |
Identity of Instrument Used to Perform this Study |
|
14 |
200 |
CE |
O |
Y |
00599 |
Coded Representation of Method |
|
15 |
1 |
ID |
O |
0136 |
00600 |
Portable |
|
16 |
1 |
CE |
O |
Y |
00601 |
Observation Producing Department/Section |
|
17 |
40 |
XTN |
O |
00602 |
Telephone Number of Section |
||
18 |
1 |
IS |
R |
0174 |
00603 |
Nature of Test/Observation |
|
19 |
200 |
CE |
O |
00604 |
Report Subheader |
||
20 |
20 |
ST |
O |
00605 |
Report Display Order |
||
21 |
26 |
TS |
O |
00606 |
Date/Time Stamp for any change in Def Attri for Obs |
||
22 |
26 |
TS |
O |
00607 |
Effective Date/Time of Change |
||
23 |
20 |
NM |
O |
00608 |
Typical Turn-Around Time |
||
24 |
20 |
NM |
O |
00609 |
Processing Time |
||
25 |
40 |
ID |
O |
Y |
0168 |
00610 |
Processing Priority |
26 |
5 |
ID |
O |
0169 |
00611 |
Reporting Priority |
|
27 |
200 |
CE |
O |
Y |
00612 |
Outside Site(s) Where Observation may be Performed |
|
28 |
1000 |
XAD |
O |
00613 |
Address of Outside Site(s) |
||
29 |
400 |
XTN |
O |
00614 |
Phone Number of Outside Site |
||
30 |
1 |
IS |
O |
0177 |
00615 |
Confidentiality Code |
|
31 |
200 |
CE |
O |
00616 |
Observations Required to Interpret the Obs |
||
32 |
64K |
TX |
O |
00617 |
Interpretation of Observations |
||
33 |
64K |
CE |
O |
00618 |
Contraindications to Observations |
||
34 |
200 |
CE |
O |
Y |
00619 |
Reflex Tests/Observations |
|
35 |
80 |
TX |
O |
00620 |
Rules that Trigger Reflex Testing |
||
36 |
64K |
CE |
O |
00621 |
Fixed Canned Message |
||
37 |
200 |
TX |
O |
00622 |
Patient Preparation |
||
38 |
200 |
CE |
O |
00623 |
Procedure Medication |
||
39 |
200 |
TX |
O |
00624 |
Factors that may Effect the Observation |
||
40 |
60 |
ST |
O |
Y |
00625 |
Test/Observation Performance Schedule |
|
41 |
64K |
TX |
O |
00626 |
Description of Test Methods |
||
42 |
60 |
CE |
O |
0254 |
00937 |
Kind of Quantity Observed |
|
43 |
60 |
CE |
O |
0255 |
00938 |
Point Versus Interval |
|
44 |
200 |
TX |
O |
00939 |
Challenge Information |
||
45 |
200 |
CE |
O |
0258 |
00940 |
Relationship Modifier |
|
46 |
200 |
CE |
O |
00941 |
Target Anatomic Site Of Test |
||
47 |
200 |
CE |
O |
0259 |
00942 |
Modality Of Imaging Measurement |
8.7.3.0 OM1 field definitions
Definition: This field contains the first OM1 segment in a message and is described as 1, the second as 2, and so on.
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field contains the producers usual or preferred identification of the test or observation. Only three components should be included: <ID code>^<service text name/description>^<source list of code>. All components should be non-null. The source list may be any of those included in ASTM Tables 3 and 5, or a local code.
Definition: This field contains the allowed data type(s) for this observation. The codes are the same as those listed for OBX (a given observation may, under different circumstances, take on different data types). Indeed, under limited circumstances, an observation can consist of one or more fragments of different data types. When an observation may have more than one data type, e.g., coded (CE) and numeric (NM) the allowable data types should be separated by repeat delimiters. Refer to HL7 table 0125 - Value type for valid values.
Definition: This field contains a flag indicating whether or not at least one specimen is required for the test/observation. Refer to HL7 table 0136 - Yes/no indicator as defined in Chapter 2.
Y one or more specimens are required to obtain this observation
N a specimen is not required
When a specimen is required, segment OM4 will usually be included (one per specimen is required).
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field uniquely identifies the service producing the observation described in this segment. Three components should be included: an identifying code, the name of the producer, and the identity of the coding system (e.g., 323-5678^Acme Special Lab^MC). The identity of the coding system will usually be MC (Medicare provider number or HIBCC site codes) in the United States. Each country may want to specify its preferred coding system and define a coding system ID to identify it.
Remember that the magnitude of a treatment or the setting on a machine, such as a ventilator, can be regarded as an observation. Thus, pharmacy, respiratory care, and nursing may be producers of such observations.
Definition: This field contains a text description of this observation.
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field contains all alias codes/identifiers for this observation. If more than one alias code needs to be specified, multiple three-component, CE-format entries (<code 1>^<name 1>^<code system 1>) may be given, separated by repeat delimiters. An observation may have as many names/codes as are applicable (e.g., ICD9, ACR-NEMA, SNOMED, and READ). We encourage the inclusion of as many different codes as may apply to assist cross-system mapping of terminology. All components of each triplet should be non-null (that is, names and coding system IDs within the CE data type are required in addition to codes). The source list may be any of those included in ASTM Tables 3 and 5.
Because the size (dose) of a treatment can also be an observation, codes that identify treatments (e.g., NDC, ICCS) may also be included in this field.
Note: In this field, the names within the CE data type are required. |
Definition: This field contains any test aliases or synonyms for the name in the context of the ordering service. These are alternative names, not associated with a particular coding system, by which the battery, test, or observation (e.g., measurement, test, diagnostic study, treatment) is known to users of the system. Multiple names in this list are separated by repeat delimiters.
Definition: This field contains the preferred name for reporting the observation or battery. The name can contain up to 30 characters (including blanks). It is the preferred name for columnar reports that require a maximum name size.
Definition: This field contains the name that can be used in space-limited reports (e.g., specimen labels) to identify the observation for the convenience of human readers. The name can contain up to eight characters.
Definition: This field contains the fully specified name for the observation or battery. It may include the full (unabbreviated) multiple-word names and contain up to 200 characters. It should be as scientifically precise as possible.
Definition: This field indicates whether or not a test/observation is an orderable code. Refer to HL7 table 0136 - Yes/no indicator for valid values.
Y the test/observation is an orderable code
N the test/observation is not orderable
For example, blood differential count is usually an orderable "test," MCV, contained within the differential count, is usually not independently orderable.
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: When applicable, this field contains the instrument or device that is used to generate this observation or battery. Examples are the automated instrument in the laboratory, the imaging device and model number in radiology, and the automatic blood pressure machine on the ward. The instrument is specified as a coded entry in anticipation that these identifiers could be specified as codes. Initially, we expect that most of the information about devices will be transmitted as text in the second component of the CE identifier. If more than one kind of instrument is used, all of them can be listed, separated by repeat delimiters.
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field contains the method(s) used to produce the observation and should be recorded in a computer-understandable (coded) form here. This field should report the same method(s) reported in narrative in the following field. More than one method may be listed, but only if they produce results that are clinically indistinguishable. Multiple methods must be separated by repeat delimiters.
Definition: This field indicates whether or not a portable device may be used for the test/observation. Refer to HL7 table 0136 - Yes/no indicator for valid values.
Y the observation can be obtained with a portable device brought to the patient
N the patient or specimen must be transported to the device
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field permits the sorting of observation orders and values by the providing services department/section. It provides "source oriented" reporting when required. The codes for this field should be taken from ASTM Table 15 (Diagnostic Service Codes). Free text may be used instead of these codes, but in that case, they should be recorded as the second "component" of the field to distinguish them from the standard codes. Multiple codes in this field are separated by repeat delimiters.
Definition: This field contains the telephone number for calling responsible parties in this section to ask results or advice about the use of this test.
Definition: This field indicates whether the definition entry identifies a test battery, an entire functional procedure or study, a single test value (observation), multiple test batteries or functional procedures as an orderable unit (profile), or a single test value (observation) calculated from other independent observations. Refer to user-defined table 0174 - Nature of test/observation for suggested values.
User-defined Table 0174 - Nature of test/observation
Value |
Description |
P |
Profile or battery consisting of many independent atomic observations (e.g., SMA12, electrolytes), usually done at one instrument on one specimen |
F |
Functional procedure that may consist of one or more interrelated measures (e.g., glucose tolerance test, creatine clearance), usually done at different times and/or on different specimens |
A |
Atomic test/observation (test code or treatment code) |
S |
Superset--a set of batteries or procedures ordered under a single code unit but processed as separate batteries (e.g., routines = CBC, UA, electrolytes) This set indicates that the code being described is used to order multiple test/observation batteries. For example, a client who routinely orders a CBC, a differential, and a thyroxine as an outpatient profile might use a single, special code to order all three test batteries, instead of having to submit three separate order codes. |
C |
Single observation calculated via a rule or formula from other independent observations (e.g., Alveolar--arterial ratio, cardiac output) |
Codes P, F, and S identify sets (batteries) and should be associated with an OM5 segment that defines the list of elements. The definitions for the contained elements would have to be sent in other independent OMx segments, one for each contained element. In the ASTM context, most text reports--such as discharge summaries, admission H&Ps, and chest x-ray reports--are considered as sets, in which each section of the report (e.g., description, impression, and recommendation of an x-ray report) is considered a separate observation.
Code A identifies a single direct observation and would usually be associated with an OM2 and/or OM3 segments.
Code C identifies a derived quantity and would usually be associated with an OM6 segment.
All of these codes can be associated with one or more OM4 (specimen) segments.
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field contains an optional string that defines the preferred header under which this observation should be listed on a standard display. For example, if the test is hemoglobin, this string might be "Complete blood count." It is represented as a coded data type so that a battery can be a header. Only the description part of the string may be included in case the subheader does not have an associated code. When a series of observations is displayed according to the sort order given below, the subheader that groups those observations is presented whenever the subheader changes.
Definition: This field contains an optional string that defines the sort order in which this observation is presented in a standard report or display that contains the many observations.
Definition: This field contains the date and time that the last of any field change was made and in the hosts record corresponding to the OM1 segment.
Definition: This field contains the date and time of the last change in the test procedure that would make previous results incompatible with new results, e.g., the last time that normal reference range or units changed for a numeric test/observation.
We strongly suggest that observation producers never use the same observation ID when the measurement procedures change in such a way that results produced under the new procedure are clinically different from those produced with the old procedure. Rather, the producer should try to adjust the new procedure so that its values are clinically indistinguishable from the old. Failing that, one should create a new observation ID for the observation produced under the new procedure.
In the rare circumstances when a procedure change occurs and neither of the above two options is viable, this field shall be used to transmit the effective date-time of the new procedure. The receiving system shall assume that any values that come across under this observation ID are under the new procedure after this date and take appropriate steps to distinguish the old from the new observations.
This number is included to provide a means of communicating with the observation producing service when they have questions about particular observations or results.
Definition: This field contains the typical processing time for single test/observation. This field indicates the time from the delivery of a specimen or transport of a patient to a diagnostic service and the completion of the study. It includes the usual waiting time. The units are measured in minutes.
Definition: This field contains the usual length of time (in minutes) between the start of a test process and its completion.
Definition: This field contains one or more available priorities for performing the observation or test. This is the priority that can be placed in OBR-28-quantity/timing. For tests that require a specimen, this field may contain two components in the format <specimen priority>^<processing priority>. The first component in this case indicates the priority with which the specimen will be collected and is the priority that is specified in an OBR segment when ordering the observation. The second component indicates the corresponding priority with which the producer service will process the specimen, produce the observation, and return results, when this differs from collection priority. Refer to HL7 table 0168 - Processing priority for valid values.
Table 0168 - Processing priority
Value |
Description |
S |
Stat (do immediately) |
A |
As soon as possible (a priority lower than stat) |
R |
Routine |
P |
Preoperative (to be done prior to surgery) |
T |
Timing critical (do as near as possible to requested time) |
C |
Measure continuously (e.g., arterial line blood pressure) |
B |
Do at bedside or portable (may be used with other codes) |
The priority for obtaining the specimen is included in OM4. Multiple priorities may be given, separated by repeat delimiters. For example, S~A~R~P~T indicates that the test may be ordered using codes S, A, R, P, or T.
Definition: This field contains the available priorities reporting the test results when the user is asked to specify the reporting priority independent of the processing priority. Refer to HL7 table 0169 - Reporting priority for valid values.
Table 0169 - Reporting priority
Value |
Description |
C |
Call back results |
R |
Rush reporting |
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field contains the identification(s) of the outside service(s) that produce the observation. The format of this CE field uses the producer ID (as defined in OM1-6-producer ID) and the name of the service separated by component delimiters. An example is 39221^ACME lab^MC. If multiple services are used, they should be separated by repeat delimiter(s).
Components: <street address (ST)> ^ <other designation (ST)> ^ <city (ST)> ^ <state or province (ST)> ^ <zip or postal code (ST)> ^ <country (ID)> ^ <address type> (ID)> ^ <other geographic designation (ST)> ^ <country/parish code (IS)> ^ <census tract (S)>
Definition: This field contains the address of the outside services listed in OM1-28-outside site(s) where observation may be performed. If multiple services are recorded in that field, their addresses should be separated by repeat delimiters, and the addresses should appear in the same order in which the services appear in the preceding field.
Components: [NNN] [(999)]999-9999 [X99999] [B99999] [C any text] ^ <telecommunication use code (ID)> ^ <telecommunication equipment type (ID)> ^ <email address (ST)> ^ <county code (NM)> ^ <area/city code (NM)> ^ <phone number (NM) ^ <extension (NM)> ^ <any text (ST)>
Definition: This field contains the telephone number of the outside site.
Definition: This field contains the degree to which special confidentiality protection should be applied to the observation. For example, a tighter control may be applied to an HIV test than to a CBC. Refer to user-defined table 0177 - Confidentiality code for suggested values.
User-defined Table 0177 - Confidentiality code
Value |
Description |
V |
Very restricted |
R |
Restricted |
U |
Usual control |
EMP |
Employee |
UWM |
Unwed mother |
VIP |
Very important person or celebrity |
PSY |
Psychiatric patient |
AID |
AIDS patient |
HIV |
HIV(+) patient |
ETH |
Alcohol/drug treatment patient |
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field contains the list of variables that the diagnostic service needs to interpret the results of an ordered study. The observations specified here should be sent to the diagnostic service as OBX segments along with the order (OBR) segment.
Example for cervical pap smear:
2000.32^date last menstrual period^AS4~2000.33^menstrual state^AS4
Example for arterial blood gas:
94700^inspired 02^AS4
These examples use AS4 codes in code/text format to identify the variables. Separate multiple items by repeat delimiters.
Definition: This field contains the clinical information about interpreting test results. Examples are the conditions (drugs) that may cause false abnormals, and the information about the sensitivity and specificity of the test for diagnoses.
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field contains the diagnosis or problem for which the test is a contraindication or of possible danger (e.g., pacemaker, pregnancy, diabetes). For example, if the test identified in OM1 was an intravenous pyelogram, this field would include warnings about the use of contrast media in diabetes. The contraindication diagnoses should be separated by repeat delimiters.
Most contraindication rules will be transmitted as free text. In such cases, the contents serves only as information for human reading. However, an alternative for machine readable contraindication rules also exists. The rule may be defined formally in the Arden Syntax (ASTM 1460-1992) which has syntax for defining algebraic and transcendental equations, as well as temporal and logical selection criteria based on patient information stored in the computer record. Reflex rules that are written in Arden Syntax should begin and end with a double semi-colon (;;), the Arden slot delimiter.
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field contains the test names as type CE (i.e., <code>^<text name>^<coding system>) that may be ordered automatically by the diagnostic service, depending on the results obtained from the ordered battery. A screening CBC might trigger a reticulocyte count if the Hgb is less than 12. Multiple reflex tests are separated by repeat delimiters.
Definition: This field contains the rules that trigger the reflex tests listed above. If multiple reflex tests are listed in OM1-34-reflex tests/observations separated by repeat delimiters, a set of corresponding rules will be included in this section. The first rule will apply to the first test, the second to the second test, and so on.
Most reflex rules will usually be transmitted as free text. In such cases, the contents serve only as information for human reading. However, an alternative for machine readable rules also exists. The rule may be defined formally in the Arden Syntax (ASTM 1460-1992) which has syntax for defining algebraic and transcendental equations, as well as temporal and logical selection criteria based on patient information stored in the computer record. Reflex rules that are written in Arden Syntax should begin and end with a double semi-colon (;;), the Arden slot delimiter.
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field contains the codes and a fixed text message that is always associated with an abbreviation. The field may include multiple messages separated by repeat delimiters.
Most rules about patient testing will be transmitted as free text. In such cases, the contents serves only as information for human reading. However, an alternative for machine readable rules also exists. The rule may be defined formally in the Arden Syntax (ASTM 1460-1992) which has syntax for defining algebraic and transcendental equations, as well as temporal and logical selection criteria based on patient information stored in the computer record. Rules about patient preparation are written in Arden Syntax should begin and end with a double semi-colon (;;), the Arden slot delimiter.
Definition: This field contains the tests or observations that require special patient preparation, diet, or medications. For GI contrast studies, this field would contain the pretest diet, e.g., low residue for two days, NPO before study, and the preferred purgatives. Each separate med, diet, or preparation should be delimited by a repeat delimiter. Separate each requirement by a repeat delimiter. Example for a sigmoidectomy: clear liquid diet full day before procedure~take 8 oz mag citrate 6pm day before procedure~take 2 ducat tabs (5m) at 4pm day before procedure~NPO past midnight.
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This field contains the treatments that may be needed as part of the procedure. Examples are radioactive iodine for a thyroid screen, and methacholine for a methacholine spirometry challenge. This field should be identified as a CE data type.
Definition: This field contains the text description of the foods, diagnoses, drugs, or other conditions that may influence the interpretation of the observation. Information about the direction of the effect, and any recommendation about altering the diet, conditions, or drug before initiating the test observation.
Most rules about factors that effect the test interpretation will be transmitted as free text. In such cases, the contents serves only as information for human reading. However, an alternative for machine readable rules also exists. The rule may be defined formally in the Arden Syntax (ASTM 1460-1992) which has syntax for defining algebraic and transcendental equations, as well as temporal and logical selection criteria based on patient information stored in the computer record. Rules about patient preparation are written in Arden Syntax and should begin and end with a double semi-colon (;;), the Arden slot delimiter.
Definition: This field contains the diagnostic studies/tests that are performed only at certain times during the course of a work day or work week. This field indicates the maximum interval between successive test performances (the test may actually be performed more frequently). The format given in Chapter 4, Section 4.4.2.1, "Repeat Pattern," should be used. If necessary, multiple codes may be given, separated by repeat delimiters. The use of multiple codes indicates that the test is performed at multiple concurrent intervals. For example, Q6H indicates that the test is performed at least once every 6 hours around the clock. QJ1 indicates that the test is performed at least every week on Mondays. QAM~QPM indicates that the test is performed at least once every morning and every evening. QJ1~QJ3~QJ5 indicates that the test is performed at least every week on Mondays, Wednesdays, and Fridays. C indicates that the test is performed continuously, 7 days per week.
Definition: This field contains the text description of the methods used to perform the text and generate the observations. Bibliographic citations may be included.
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definitions: This optional attribute describes the underlying kind of property represented by this observation. This attribute distinguishes concentrations from total amounts, molar concentrations from mass concentrations, partial pressures from colors, and so forth. These are discussed more fully in the LOINC Users Manual.1 They are derived from the approach described in 1995 edition of the IUPAC Silver Book. [ International Union of Pure and Applied Chemistry/International Federation of Clinical Chemistry. The Silver Book: Compendium of terminology and nomenclature of properties in clinical laboratory sciences. Oxford: Blackwell Scientific Publishers, 1995.] These distinctions are used in IUPAC and LOINC standard codes. Defined categories are listed in HL7 table 0254 - Kind of quantity.
The distinctions of true quantities in this table are based primarily on dimensional analyses. The table contains a number of "families," those related to simple counts (number, number concentration, etc.), to mass (mass, mass concentration, etc.), to enzyme activity (catalytic content, catalytic concentration, etc.), and molar or equivalents (substance content, substance concentration).
By this classification, a glucose (in the US) would be classed as a mass concentration. A sodium would be classed as a substance concentration. Within the family, a total amount should be described as the unadorned variant; e.g., the property of measure for a patients weight would be mass, not mass content. Most chemical measures produce concentrations, as exemplified by sodium and glucose. However, a 24-hour urine protein is not a mass concentration, but a mass rate (mass per unit time). The content variants (e.g., mass content, substance content) are used to reflect an amount per mass (usually) of tissue.
This attribute would be valued in a master file only if the service sending the master file classified observations by their principle of measurement.
Table 0254 - Kind of quantity
Enzymatic Activity |
Other Properties | ||
CACT |
*Catalytic Activity |
ABS |
Absorbance |
CNC |
*Catalytic Concentration |
ACT |
*Activity |
CCRTO |
Catalytic Concentration Ratio |
APER |
Appearance |
CCNT |
*Catalytic Content |
ARB |
*Arbitrary |
CFR |
*Catalytic Fraction |
AREA |
Area |
CRAT |
*Catalytic Rate |
ASPECT |
Aspect |
CRTO |
Catalytic Ratio |
CLAS |
Class |
Entitic |
CNST |
*Constant |
|
ENT |
*Entitic |
COEF |
*Coefficient |
ENTSUB |
*Entitic Substance of Amount |
COLOR |
Color |
ENTCAT |
*Entitic Catalytic Activity |
CONS |
Consistency |
ENTNUM |
*Entitic Number |
DEN |
Density |
ENTVOL |
*Entitic Volume |
DEV |
Device |
Mass |
DIFF |
*Difference |
|
MASS |
*Mass |
ELAS |
Elasticity |
MCNC |
*Mass Concentration |
ELPOT |
Electrical Potential (Voltage) |
MCRTO |
*Mass Concentration Ratio |
ELRAT |
Electrical current (amperage) |
MCNT |
Mass Content |
ELRES |
Electrical Resistance |
MFR |
*Mass Fraction |
ENGR |
Energy |
MINC |
*Mass Increment |
EQL |
Equilibrium |
MRAT |
*Mass Rate |
FORCE |
Mechanical force |
MRTO |
*Mass Ratio |
FREQ |
Frequency |
Counts |
IMP |
Impression/ interpretation of study |
|
NUM |
*Number |
KINV |
*Kinematic Viscosity |
NCNC |
*Number Concentration |
LEN |
Length |
NCNT |
*Number Content |
LINC |
*Length Increment |
NFR |
*Number Fraction |
LIQ |
*Liquifaction |
NRTO |
*Number Ratio |
MGFLUX |
Magnetic flux |
Substance Amount (Moles/Millequivalents) |
MORPH |
Morphology |
|
SUB |
*Substance Amount |
MOTIL |
Motility |
SCNC |
*Substance Concentration |
OD |
Optical density |
SCRTO |
*Substance Concentration Ratio |
OSMOL |
*Osmolality |
SCNT |
*Substance Content |
PRID |
Presence/Identity/Existence |
SCNTR |
*Substance Content Rate |
PRES |
*Pressure (Partial) |
SFR |
*Substance Fraction |
PWR |
Power (wattage) |
SCNCIN |
*Substance Concentration Increment |
RANGE |
*Ranges |
SRAT |
*Substance Rate |
RATIO |
*Ratios |
SRTO |
*Substance Ratio |
RDEN |
*Relative Density |
Volumes |
REL |
*Relative |
|
VOL |
*Volume |
SATFR |
*Saturation Fraction |
VCNT |
*Volume Content |
SHAPE |
Shape |
VFR |
*Volume Fraction |
SMELL |
Smell |
VRAT |
*Volume Rate |
SUSC |
*Susceptibility |
VRTO |
*Volume Ratio |
TASTE |
Taste |
Miscellaneous Unit Measures |
TEMP |
*Temperature |
|
ACNC |
Concentration, Arbitrary Substance |
TEMPDF |
*Temperature Difference |
RLMCNC |
*Relative Mass Concentration |
TEMPIN |
*Temperature Increment |
RLSCNC |
*Relative Substance Concentration |
TITR |
*Dilution Factor (Titer) |
THRMCNC |
*Threshold Mass Concentration |
TYPE |
*Type |
THRSCNC |
*Threshold Substance Concentration |
VEL |
*Velocity |
Time |
VELRT |
*Velocity Ratio |
|
TIME |
*Time (e.g. seconds) |
VISC |
*Viscosity |
TMDF |
*Time Difference | ||
TMSTP |
*Time Stamp -- Date and Time | ||
TRTO |
*Time Ratio | ||
RCRLTM |
*Reciprocal Relative Time | ||
RLTM |
*Relative Time | ||
*Starred items are adopted from the IUPAC Silver Book,2 non-starred items are extensions. |
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This optional attribute allows master files to classify observations as measuring the patients state at a point in time (e.g., spot urines, random urines, serum potassium), or averaged over a interval of time (e.g., concentration, total amount, or clearance over a 24-hour collection). Interval measures most often apply to urine and stool specimens (e.g., 24-hour urines, 3-day stool fats). They also apply to clinical measurements such as urine outputs, which are reported as shift totals and 24-hour totals, and event counts on physiologic monitors such as the number of PVCs on a 24-hour Holter monitor.
This field would only be valued in a transaction if the service sending this master file message classified its observation by point versus time interval. This field is not used to record the time collection interval for a particular sample. It is used to specify a characteristic of an observation which has a defined normal range and to distinguish observations of the same kind but observed over varying periods of time. A spot urine sodium would have PT stored in this field. A 24-hour urine sodium and a 24-hour Holter monitor would have 24H stored here. This attribute would only be valued if the filling service classified its observations by timing. Refer to user-defined table 0255 - Duration categories for suggested values.
User-defined Table 0255 - Duration categories
PT |
To identify measures at a point in time. This is a synonym for "spot" or "random" as applied to urine measurements. | ||||
* (star) |
Life of the "unit." Used for blood products. | ||||
30M |
30 minutes |
7H |
7 hours |
6D |
6 days |
1H |
1 hour |
8H |
8 hours |
1W |
1 week |
2H |
2 hours |
12H |
12 hours |
2W |
2 weeks |
2.5H |
2½ hours |
24H |
24 hours |
3W |
3 weeks |
3H |
3 hours |
2D |
2 days |
4W |
4 weeks |
4H |
4 hours |
3D |
3 days |
1L |
1 months (30 days) |
5H |
5 hours |
4D |
4 days |
2L |
2 months |
6H |
6 hours |
5D |
5 days |
3L |
3 months |
Definition: This optional attribute provides information for classifying observations by the challenge component of the test, if a challenge does speciate the observation. For example, distinguishing tests that have a challenge component in database. There co-ascribes the physiologic or drug challenge that is intrinsic to the measurement. To identify, for example, tests that include a glucose challenge.
To construct this text string, use the following template. (Note: This field is not constructed of formally defined components; it is a free text field. Component delimiters are not used and it is not necessary to supply placeholders if some "components" are not used.)
The time delay follows the syntax: n<S|M|H|D|W> where n is a number (possibly a decimal); S denotes seconds; M denotes minutes; H denotes hours; D denotes days; and W denotes weeks. The time delay can be preceded by a greater than (>) sign, e.g. >4H.
HL7 table 0256 - Time delay post challenge lists possible values for time delay.
Examples
PRE 100 GM GLUCOSE PO
PRE 100 GM GLUCOSE PO
30M POST 100 GM GLUCOSE PO
2H POST 100 GM GLUCOSE PO
TROUGH
For drug peak and trough measures the nature of the substance challenged is the same as the analyte name, and need not be included.
We denote the route of the challenge via abbreviations for medication routes (see Chapter 4, Section 4.8.3.1, "Route," HL7 table 0162 - Route of administration). An oral route of administration would be denoted by "PO," an intravenous route by "IV."
Details of the drug dose, time the dose was given, route of administration, etc., would be noted in separate OBX, and would have corresponding master observation definitions stored in the observation master file map to different records stored in the master file segments contained in the drug level message.
Table 0256 - Time delay post challenge
BS Baseline (time just before the challenge) PEAK The time post drug dose at which the highest drug level is reached (differs by drug) TROUGH The time post drug dose at which the lowest drug level is reached (varies with drug) RANDOM Time from the challenge, or dose not specified. (random) | |
n minutes/hours/days/weeks/months/etc. after challenge begun: | |
1M 1 minute post challenge 2M 2 minutes post challenge 3M 3 minutes post challenge 4M 4 minutes post challenge 5M 5 minutes post challenge 6M 6 minutes post challenge 7M 7 minutes post challenge 8M 8 minutes post challenge 9M 9 minutes post challenge 10M 10 minutes post challenge 15M 15 minutes post challenge 20M 20 minutes post challenge 25M 25 minutes post challenge 20M 30 minutes post challenge 1H 1 hour post challenge 2H 2 hours post challenge 2.5H 2 1/2 hours post challenge 3H 3 hours post challenge 4H 4 hours post challenge 5H 5 hours post challenge |
6H 6 hours post challenge 7H 7 hours post challenge 8H 8 hours post challenge 8H SHIFT 8 hours aligned on nursing shifts 12H 12 hours post challenge 24H 24 hours post challenge 2D 2 days 3D 3 days 4D 4 days 5D 5 days 6D 6 days 7D 7 days 1W 1 week 10D 10 days 2W 2 weeks 3W 3 weeks 4W 4 weeks 1L 1 month (30 days) post challenge 2L 2 months (60 days) post challenge 3L 3 months (90 days) post challenge |
The nature of a physiologic (non-drug) challenge may also be specified, using the terms in HL7 table 0257 - Nature of challenge.
Table 0257 - Nature of challenge
Value |
Description |
CFST |
Fasting (no calorie intake) for the period specified in the time component of the term, e.g., 1H POST CFST |
EXCZ |
Exercise undertaken as challenge (can be quantified) |
FFST |
No fluid intake for the period specified in the time component of the term |
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This optional attribute provides a mechanism for classifying observations according to the subject, in relation to the patient whose results might be stored with as "patient" data. It is standard practice, for example, to report values for controls, donors, and blood product units as well as the patients own values, and store them in the patients record. (This may not be the best way to model such information, but it is the way it is usually reported.) This should be valued when two values (e.g., one for patient and one for a blood product unit) could otherwise be confused.
The default value is "Patient," and if not specified, this value is assumed. The persons sub-component can refer to HL7 table 0258 - Relationship modifier for valid values.
Table 0258 - Relationship modifier
Value |
Description |
CONTROL |
Control |
PATIENT |
Patient |
DONOR |
Donor |
BPU |
Blood product unit |
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This optional attribute formally indicates the site of the observation (to make it easy for a system to find all tests related to one anatomic site). It can be used to classify the observation by target site of the examination. For example, "heart" might be recorded as the target of the electrocardiogram, cardiac echo, and thallium exercise test. This attribute would be applicable to most imaging and electro-physiologic examinations. The SNOMED topology axis is an example of a coding system for anatomic sites. User-defined tables may also apply here.
Components: <identifier (ST)> ^ <text (ST)> ^ <name of coding system (ST)> ^ <alternate identifier (ST)> ^ <alternate text (ST)> ^ <name of alternate coding system (ST)>
Definition: This optional attribute describes the modality used to classify the observations, e.g., radiograph, ultrasound, CT scan, NMR, etc.. This attribute is especially important for imaging studies. Refer to user-defined table 0259 - Modality for suggested values; it is adopted from DICOM C.7.3.1.1.1 Modality. If these are used, the code source ID would be DCM.
User-defined Table 0259 - Modality
Value |
Description |
Value |
Description |
AS |
Angioscopy |
FS |
Fundoscopy |
BS |
Biomagnetic Imaging |
LP |
Laparoscopy |
CD |
Color Flow Doppler |
LS |
Laser Surface Scan |
CP |
Colposcopy |
MA |
Magnetic Resonance Angiography |
CR |
Computed Radiography |
MS |
Magnetic Resonance Spectroscopy |
CS |
Cystoscopy |
NM |
Nuclear Medicine (radioisotope study) |
CT |
Computed Tomography |
OT |
Other |
DD |
Duplex Doppler |
PT |
Positron Emission Tomography (PET) |
DG |
Diapanography |
RF |
Radio Fluoroscopy |
DM |
Digital Microscopy |
ST |
Single Photon Emission Computed Tomography (SPECT) |
EC |
Echocardiography |
TG |
Thermography |
ES |
Endoscopy |
US |
Ultrasound |
FA |
Fluorescein Angiography |
XA |
X-Ray Angiography |