18.8.100.36 OM1-35 Rules that Trigger Reflex Testing (TX) 00620 (8.8.9.35)

Definition: This field contains the rules that trigger the reflex tests listed above. If multiple reflex tests are listed in OM1-34 - Reflex Text/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.

18.8.100.37 OM1-36 Fixed Canned Message (CWE) 00621 (8.8.9.36)

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. Refer to Table 0643 - Fixed Canned Message in Chapter 2C for valid values.

Most rules about patient testing will 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. Rules about patient preparation are written in Arden Syntax should begin and end with a double semi-colon (;;), the Arden slot delimiter.

18.8.100.38 OM1-37 Patient Preparation (TX) 00622 (8.8.9.37)

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.|...

18.8.100.39 OM1-38 Procedure Medication (CWE) 00623 (8.8.9.38)

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 CWE data type. Refer to Table 0644 - Procedure Medication in Chapter 2C for valid values.

18.8.100.40 OM1-39 Factors That May Affect the Observation (TX) 00624 (8.8.9.39)

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 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. Rules about patient preparation are written in Arden Syntax and should begin and end with a double semi-colon (;;), the Arden slot delimiter.

18.8.100.41 OM1-40 Service/Test/Observation Performance Schedule (ST) 00625 (8.8.9.40)

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 4.3.2.1, "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.

18.8.100.42 OM1-41 Description of Test Methods (TX) 00626 (8.8.9.41)

Definition: This field contains the text description of the methods used to perform the text and generate the observations. Bibliographic citations may be included.

18.8.100.43 OM1-42 Kind of Quantity Observed (CWE) 00937 (8.8.9.42)

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. They are derived from the approach described in 1995 edition of the IUPAC Silver Book. These distinctions are used in IUPAC and LOINC standard codes. Defined categories are listed in HL7 Table 0254 - Kind of Quantity in Chapter 2C, Code Tables.

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 patient's 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.

18.8.100.44 OM1-43 Point Versus Interval (CWE) 00938 (8.8.9.43)

Definition: This optional attribute allows master files to classify observations as measuring the patient's state at a point in time (e.g., spot urines, random urines, serum potassium), or averaged over an 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 in Chapter 2C, Code Tables, for suggested values.

18.8.100.45 OM1-44 Challenge Information (TX) 00939 (8.8.9.44)

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 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 in Chapter 2C, Code Tables, 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 4A, section 4A.4.2.1, "Route," which references HL7 Table 0162 - Route of Administration in Chapter 2C, Code Tables). 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.

The nature of a physiologic (non-drug) challenge may also be specified, using the terms in HL7 Table 0257 - Nature of challenge in Chapter 2C, Code Tables.

18.8.100.46 OM1-45 Relationship Modifier (CWE) 00940 (8.8.9.45)

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 patient's own values, and store them in the patient's 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 in Chapter 2C, Code Tables, for valid values.

18.8.100.47 OM1-46 Target Anatomic Site of Test (CWE) 00941 (8.8.9.46)

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. Refer to Table 0645 - Target Anatomic Site Of Test in Chapter 2C for valid values.

18.8.100.48 OM1-47 Modality of Imaging Measurement (CWE) 00942 (8.8.9.47)

Definition: This optional attribute describes the modality used to acquire the observation data, e.g., radiograph, ultrasound, CT scan, MR, etc. This attribute is especially important for imaging studies. Refer to External Table 0910 - Acquisition Modality in Chapter 2C, Code Tables, for the defined value set, which may be repalce or extended with local codes. If the DICOM codes are used, the coding system ID is DCM.

Note: The use of User-defined Table 0259 - Modality for this field is deprecated and retained for backward compatibility as of v 2.7.

18.8.100.49 OM1-48 Exclusive Test (ID) 03310 (8.8.9.48)

Definition: This field defines if this test should be a specific event with no other tests to be performed with this test. Refer to HL7 Table 0919 - Exclusive Test in Chapter 2C, Code Tables, for valid values.

If not populated, the default value of "N" is assumed and that this test can be included with any number of other tests.

When D is specified for this field, using field OM1-49 determines how tests must be grouped together. Tests within the same Diagnostic Service Sector may be on the same requisition, and therefore in the same message.

18.8.100.50 OM1-49 Diagnostic Serv Sect ID (ID) 00257 (8.8.9.49)

Definition: This field is the section of the diagnostic service where the observation was performed. If the study was performed by an outside service, the identification of that service should be recorded here. Refer to HL7 Table 0074 - Diagnostic Service Section ID in Chapter 2C, Code Tables, for valid entries. Same as OBR-24.

18.8.100.51 OM1-50 Taxonomic Classification Code (CWE) 01539 (8.8.9.50)

Definition: The species of living organism. This may include the common or scientific name, based on the coding system(s) used. SNOMED is the recommended coding system. If this field is not valued, a human is assumed. Refer to User-defined Table 0446 - Species Code in Chapter 2C, Code Tables, for suggested values.

For example:

...|L-80700^Canine, NOS^SNM3|...

...|L-80100^Bovine^SNM3|...

...|L-80A00^Feline^SNM3|....

This field is a list of species or other taxonomic classification(s) to which the indicated specimen type may appropriately be applied for the indicated observation or test. If this field is omitted the default meaning is that the test or observation is applicable to humans. In a veterinary context if the test is applicable to any species, an appropriate code such as "Kingdom Animalia (organism)" should be used to avoid confusion with the meaning of human only.

18.8.100.52 OM1-51 Other Names (recognized by the producer for the observation) (ST) 03399 (8.8.9.51)

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, etc.) is known to users of the system. Multiple names in this list are separated by repeat delimiters.

18.8.100.53 OM1-52 Replaced Producer's Service/Test Observation ID (CWE) 03433 (8.8.9.52)

Definition: This field is used in conjunction with a MFE-1 Record-Level Event Code 'MDC' defined as: "Deactivate: discontinue using record in master file, but do not delete from database", in conjunction with an OM1 segment providing detail for the deactivate code. When the OM1-2 Producer's Service/Test/Observation ID is being deactivated, use OM1-52 to indicate the producer's replacement test or observation code(s), as it was defined in the OM1-2 Producer's Service/Test/Observation ID when the new/replacement code was added. Refer to Table 0646 - Replacement Producer's Service/Test/Observation ID in Chapter 2C for valid values.

Table below for information in change request proposal process and not intended for inclusion in the base standard:

MFI-3

REP

MAD - Add record to master file

UPD

MDC - Deactivate: discontinue using record in master file, but do not delete from database

UPD

18.8.100.54 OM1-53 Prior Results Instructions (TX) 03434 (8.8.9.53)

Definition: This field is used to indicate when the test in OM1-2 Producer's Service/Test/Observation ID is ordered, prior results should accompany the order (OML^O21^OML_O21: Laboratory Order Message). For example, when ordering a Thyroid FNA (Fine Needle Aspiration) Evaluation, send the prior results of Ultrasound Findings. The instructions may also indicate a timeframe; for example, send the prior results of CBC in past 60 days.

18.8.100.55 OM1-54 Special Instructions (TX) 03435 (8.8.9.54)

Definition: This field is used to convey special instructions for the test, for example: "Chain-of-custody documentation is required for samples submitted for pre-employment, random employee testing, and forensic purposes. For other applications, use the standard request form." (Note: this is for toxicology testing); "If reflex test is performed, additional charges/CPT code(s) may apply."; "Please direct any questions regarding this test to Oncology Customer Service"; "Please include tentative diagnosis/treatment on the request form. This is necessary for proper culturing and result interpretation." (Note: this is for chromosome analysis.)

18.8.100.56 OM1-55 Test Category (CWE) 03436 (8.8.9.55)

Definition: This field may be used to organize tests for display or other user defined purpose. For example, tests might be categorized by disease state, such as molecular tests for solid tumors; example categories are: breast, colorectal, lung, and melanoma.

18.8.100.57 OM1-56 Observation/Identifier associated with Producer’s Service/Test/Observation ID (CWE) 03437 (8.8.9.56)

Definition: This field contains the code for resulted tests, which are associated with the Producer’s Service/Test/Observation ID code in OM1-2 and will appear in OBX-3 Observation Identifier in a result message. Refer to Table 0647 - Observation/Identifier associated with Producer’s Service/Test/Observation ID in Chapter 2C for valid values.

18.8.100.58 OM1-57 Typical Turn-Around Time (CQ) 03438 (8.8.9.57)

Definition: This field contains the typical processing time for single test/observation. This field indicates the time from 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.

18.8.100.59 OM1-58 Gender Restriction (CWE) 03439 (8.8.9.58)

Definition: This field is used to convey gender restrictions for ordering the test specified in OM1-2 Producer's Service/Test/Observation ID. If there are no restrictions the field is left empty. If the test is restricted to order for certain gender(s), the restricted genders are listed. For example, a Prostate Specific AG (PSA) test is typically ordered only for male patients, thus for PSA the field would be valued 'M' for Male. Refer to User-defined Table 0001 - Administrative Sex in Chapter 2C, Code Tables, for suggested values.

18.8.100.60 OM1-59 Age Restriction (NR) 03440 (8.8.9.59)

Definition: This field is used to convey age restrictions for ordering the test specified in OM1-2 Producer's Service/Test/Observation ID. If there are no restrictions the field is left empty. If the test is restricted to order for certain age(s), the age range restriction(s) are listed in years. For example, newborn tests are typically restricted to age 1 year or below, thus for newborn tests the field would be valued 0^1.