The OBX segment is used to transmit a single observation or observation fragment. It represents the smallest indivisible unit of a report. Its structure is summarized in Figure 7-7.

Its principal mission is to carry information about observations in report messages. But the OBX can also be part of an observation order (see Section 4.2). In this case, the OBX carries clinical information needed by the filler to interpret the observation the filler makes. For example, an OBX is needed to report the inspired oxygen on an order for a blood oxygen to a blood gas lab, or to report the menstrual phase information which should be included on an order for a pap smear to a cytology lab. Appendix 7.A includes codes for identifying many of pieces of information needed by observation producing services to properly interpret a test result.

16
C.LenElementv2.1FHIR
1..4-SIO1-00569OBX-1Set ID - Observational Simple2-
2..2-IDR1012500570OBX-2Value Type2-
3..80-CER1-00571OBX-3Observation IdentifierName3 mappings
4..20-STC1-00572OBX-4Observation Sub-ID32 mappings
5..65536-variesC1-00573OBX-5Observation Value453 mappings
6..60-CEO1-00574OBX-6Units412 mappings
7..60-STO1-00575OBX-7References Range22 mappings
8..10-IDO5007800576OBX-8Abnormal Flags32 mappings
9..5-NMO1-00577OBX-9Probability2-
10..5-IDO1008000578OBX-10Nature of Abnormal TestName4 mappings
11..2-IDR1008500579OBX-11Observation result status212 mappings
12..26-TSO1-00580OBX-12Effective date last observation normal values3-
13..20-STO1-00581OBX-13User Defined Access ChecksNEW-
14..26-TSO1-00582OBX-14Date / time of the observationNEW2 mappings
15..60-CEO1-00583OBX-15Producer's IDNEW2 mappings
16..60-CN_PHYSICIANO1-00584OBX-16Responsible ObserverNEW6 mappings
35

Editorial Comments for OBX3

Field 2

--> 7.3.2.2

BSW
Field 14

--> 7.3.2.14

BSW
Field 13

--> 7.3.2.13

BSW