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TCD - Test Code Detail Segment

The test code detail segment contains the data necessary to perform operations or calculations, or execute decisions by the laboratory automation system, and which are not supported by the original HL7 segments related to orders (ORC, OBR). For detail of use see messages of laboratory orders and observations in chapters 4 and 7.

HL7 Attribute Table - TCD - Test Code Detail Segment
Seq# DataElement Description Must Implement Flags Cardinality Length C.LEN Vocabulary DataType
TCD
1 00238 Universal Service Identifier SHALL [1..1] CWE
2 01420 Auto-Dilution Factor [0..1] SN
3 01421 Rerun Dilution Factor [0..1] SN
4 01422 Pre-Dilution Factor [0..1] SN
5 01413 Endogenous Content of Pre-Dilution Diluent [0..1] SN
6 01416 Automatic Repeat Allowed [0..1] [1..1] ID
7 01424 Reflex Allowed [0..1] [1..1] ID
8 01425 Analyte Repeat Status [0..1] CWE
9 03490 Specimen Consumption Quantity [0..1] CQ
10 03493 Pool Size [0..1] NM
11 03494 Auto-Dilution Type [0..1] CWE

TCD-1: Universal Service Identifier (CWE) 00238

(Definition from OBR.4 in Ch. 4)

Definition: This field contains the identifier code for the requested observation/test/battery. The identifier can come from either a local coding system or industry standards. Examples may be LOINC (emerging as the global standard for observation identifiers), JLAC10, or SNOMED CT. Refer to Table 0612 - Universal Service Identifier in Chapter 2C for valid values.

(Definition from OBR.4 in Ch. 7)

Definition: This field contains the identifier code for the requested observation/test/battery. The identifier can come from either a local coding system or industry standards. Examples may be LOINC (emerging as the global standard for observation identifiers), JLAC10, or SNOMED CT. Refer to Table 0612 - Universal Service Identifier in Chapter 2C for valid values.

(Definition from OM7.2 in Ch. 8)

Definition: This field contains the producer's usual or preferred identification of the test or service.

(Definition from AIS.3 in Ch. 10)

Definition: This field contains an identifier code for a service to be scheduled. This field may contain a universal service identifier describing the observation/test/battery/procedure or other activity that is to be performed during the requested appointment, similar to the universal service identifier defined for the OBR segment in the Order Entry chapter (Chapter 4). This code can be based on local and/or universal codes. The use of universal codes is recommended.

(Definition from TCC.1 in Ch. 13)

Definition: This field identifies the test code that information is being transmitted about. The alternate elements represent the test code identifier that has been assigned by the manufacturer to this particular test code. Refer to Table 0787 - Universal Service Identifier in Chapter 2C for valid values.

(Definition from TCD.1 in Ch. 13)

Definition: This field identifies the test code that information is being transmitted about. Refer to Table 0789 - Universal Service Identifier in Chapter 2C for valid values.

TCD-2: Auto-Dilution Factor (SN) 01420

Definition: This field is the value that is to be used as the factor for automatically diluting a particular specimen by an instrument for this particular test code. (See examples in definition of 13.4.3.29, "SAC-29 Dilution Factor (SN) 01356," in the "Specimen Container Detail Segment.")

TCD-3: Rerun Dilution Factor (SN) 01421

Definition: This field is the value that is to be used as the factor for automatically diluting a particular specimen in case of rerun for this particular test code.

TCD-4: Pre-Dilution Factor (SN) 01422

Definition: This field is the value that is to be used as the factor for a particular specimen that is delivered to the automated system as pre-diluted for this particular test code.

TCD-5: Endogenous Content of Pre-Dilution Diluent (SN) 01413

(Definition from TCC.7 in Ch. 13)

Definition: This field represents a baseline value for the measured test that is inherently contained in the diluent. In the calculation of the actual result for the measured test, this baseline value is normally considered.     

(Definition from TCD.5 in Ch. 13)

Definition: This field represents the rest concentration of the measured test in the diluent. It is the value that is to be used for calculation of the concentration of pre-diluted specimens for this particular test code.

TCD-6: Automatic Repeat Allowed (ID) 01416

(Definition from TCC.10 in Ch. 13)

Definition: This field identifies whether or not automatic repeat testing is to be initiated on specimens for this particular test code. Refer to HL7 Table 0136 -Yes/no Indicator for valid values.

(Definition from TCD.6 in Ch. 13)

Definition: This field identifies whether or not automatic repeats are to be initiated for this particular specimen for this particular test code. Refer to HL7 Table 0136 -Yes/no Indicator for valid values.

TCD-7: Reflex Allowed (ID) 01424

Definition: This field identifies whether or not automatic or manual reflex testing is to be initiated for this particular specimen. Refer to HL7 Table 0136 -Yes/no Indicator for valid values.

TCD-8: Analyte Repeat Status (CWE) 01425

Definition: This field identifies the repeat status for the analyte/result (e.g., original, rerun, repeat, reflex). Refer to HL7 Table 0389 – Analyte Repeat Status in Chapter 2C, Code Tables, for valid values.

For purpose of this chapter we assume the following:

TCD-9: Specimen Consumption Quantity (CQ) 03490

Definition: The specimen consumption quantity determines how much of the specimen shall be consumed in each run of the test. For some types of equipment, observation accuracy depends on this parameter.

TCD-10: Pool Size (NM) 03493

Definition: In order submission messages, this field defines the maximal size of the pool where the given specimen may be combined into. In result submission messages, this field defines the actual size of such pool.

TCD-11: Auto-Dilution Type (CWE) 03494

Definition: This field contains a vendor-defined code of the auto-dilution factor pre-configured on the instrument, which can be used instead of TCD-2 “Auto-Dilution Factor”. Refer to User-defined Table 0945– Auto Dilution Type in Chapter 2C, Code Tables, for suggested values.

If both TCD-2 “Auto-Dilution Factor” and TCD-11 “Auto-Dilution Type” are populated, they shall not contradict each other.