OM3 - Categorical Service/Test/Observation Segment

The Technical Steward for the OM3 segment is Orders and Observations.

This segment applies to free text and other non-numeric data types.

HL7 Attribute Table - OM3 - Categorical Service/Test/Observation Segment

Seq#	Data Element Name	DataType	Usage	Vocabulary	Cardinality	Item #	Length	C.LEN	Flags
OM3
1	Sequence Number - Test/Observation Master File	NM	O		[0..1]	00586		4	#
2	Preferred Coding System	CWE	O	0650	[0..1]	00636
3	Valid Coded "Answers"	CWE	O	0652	[0..*]	00637
4	Normal Text/Codes for Categorical Observations	CWE	O	0654	[0..*]	00638
5	Abnormal Text/Codes for Categorical Observations	CWE	O	0655	[0..*]	00639
6	Critical Text/Codes for Categorical Observations	CWE	O	0656	[0..*]	00640
7	Value Type	ID	O	0125(R) Value Type(Required)	[0..1]	00570	[2..3]

OM3-1: Sequence Number - Test/Observation Master File (NM) 00586

Definition: This field contains the same value as the sequence number of the associated OM1 segment.

OM3-2: Preferred Coding System (CWE) 00636

Definition: This field contains the observations whose categorical responses are taken from a specified table of codes (e.g., CWE data types). Record the preferred coding system for these responses as observations (e.g., ICD10, HGVS, ISCN, SNOMED CT). Refer to Table 0650 - Preferred Coding System in Chapter 2C for valid values.

OM3-3: Valid Coded "Answers" (CWE) 00637

Definition: This field contains a list of valid coded answers. In the case that the list of coded answers is easily enumerated, list the valid coded answers for this observation here using the preferred coding system given in OM3-2 - Preferred Coding System. If, for example, the given observation was VDRL, the valid answers might be "non-reactive", "86^ intermediate", and "87^ reactive".Refer to Table 0652 - Valid Coded "Answers" in Chapter 2C for valid values.

OM3-4: Normal Text/Codes for Categorical Observations (CWE) 00638

Definition: Certain observations/tests with a nature code of A or C (see OM1-18 - Nature of Service/Test/Observation) have text (alpha) results (e.g., reactive, nonreactive). Alpha normals for those tests should be entered in this field (e.g., "nonreactive"). Refer to Table 0654 - Normal Text/Codes for Categorical Observations in Chapter 2C for valid values.

The format of this field is:

The first component is a code taken from a standard code source list. The second component is the text associated with the code. The third component is the identification of the code table source. When only a text description of a possible answer is available, it is recorded as ^<text>.

Care should be taken to transmit only those results that are considered normal for that test. A drug screen may have possible results of "negative" and "positive." However, only a result of "negative" is considered to be normal. When an observation has more than one "normal" result, multiple values in this field should be separated with a repeat delimiter.

OM3-5: Abnormal Text/Codes for Categorical Observations (CWE) 00639

Definition: This field contains the list of the text answers that are abnormal for the test. Refer to Table 0655 - Abnormal Text/Codes for Categorical Observations in Chapter 2C for valid values.

OM3-6: Critical Text/Codes for Categorical Observations (CWE) 00640

Definition: This field contains the list of coded results that are critically abnormal for this observation. Refer to Table 0656 - Critical Text/Codes for Categorical Observations in Chapter 2C for valid values.

OM3-7: Value Type (ID) 00570

Definition: This field contains the allowed data type for a single categorical observation (code A or C in OM1-18 - Nature of Observation). Refer to HL7 Table 0125 – Value Type in Chapter 2C, Code Tables, for valid values.