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Test Code NAT2 N-Acetyltransferase 2 Gene (NAT2), Full Gene Sequence

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Identifying patients who may require isoniazid dosing adjustments

Method Name

Polymerase Chain Reaction (PCR) Followed by DNA Sequence Analysis

Reporting Name

NAT2, Full Gene Sequence

Specimen Type

Whole Blood EDTA

Specimen Required

Multiple whole blood EDTA genotype tests can be performed on a single specimen after a single extraction. See Multiple Whole Blood EDTA Genotype Tests in Special Instructions for a list of tests that can be ordered together.


Container/Tube: Lavender top (EDTA)

Specimen Volume: 3 mL

Collection Instructions: Send specimen in original tube.

Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole Blood EDTA Ambient (preferred)

Reject Due To









Reference Values

An interpretive report will be provided.


The wild-type (normal) genotype for NAT2 is *4. This is the most commonly occurring allele in some, but not all, ethnic groups.(5)


Individuals are classified as being slow, intermediate, or fast acetylators depending on their diplotypes. Slow acetylators have 2 slow haplotypes, fast acetylators have 2 fast haplotypes, and intermediate acetylators have 1 of each.


Slow acetylators receiving isoniazid therapy should be monitored for signs of toxicity.


Dose reductions may be considered for both slow and intermediate acetylators. However, it should be verified that the reduced isoniazid dose produces serum levels within the therapeutic range.

Day(s) and Time(s) Performed


Analytic Time

7 days (Not reported Saturday or Sunday)

Specimen Retention Time

Whole Blood: 2 weeks Extracted DNA: 2 months

Test Classification

This test was developed and its performance characteristics determined by Laboratory Medicine and Pathology, Mayo Clinic. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81479-Unlisted molecular pathology procedure

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NAT2 NAT2, Full Gene Sequence 90259-3


Result ID Test Result Name Result LOINC Value
NAT2S NAT2, Gene Sequencing 90259-3
57009 NAT2 Full Gene Interpretation 69047-9
57010 Haplotype 1 84414-2
57011 Haplotype 2 84414-2
57012 Haplotype 3 84414-2
57013 Haplotype 4 84414-2
57014 111T>C In Process
57015 190C>T In Process
57016 191G>A In Process
57017 282C>T In Process
57018 341T>C In Process
57019 364G>A In Process
57020 411T>A In Process
57021 434A>C In Process
57022 481C>T In Process
57023 499G>A In Process
57024 590G>A In Process
57025 759C>T In Process
57026 803A>G In Process
57027 845A>C In Process
57028 857G>A In Process
57029 859T>C/del In Process
57031 Reviewed By 18771-6

Profile Information

Test ID Reporting Name Available Separately Always Performed
NAT2F NAT2, Full Gene Sequence No Yes
NAT2S NAT2, Gene Sequencing No Yes


1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.

2. If not ordering electronically, complete, print, and send a Pharmacogenomics Test Request (T797) with the specimen.