HCV Genotype by Sequencing
Label Mnemonic: HCV GEN SEQ
Epic code: LAB8186
Downtime form: A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery
Commercial Mailout Laboratory
6240-8 RCP
356-8593
Specimen(s):
Plasma
Collection Medium:
and
Pink top tube 6 mL (K2-EDTA) Pink top tube 6 mL (K2-EDTA)
Minimum:
Collect one full Pink top tube (EDTA). If HCV Quantitation is also requested, please obtain a second full Pink top tube. Testing requires a dedicated collection tube. All collection tubes need to be processed within six hours of collection.

Preferred Minimum: 2 mL plasma
Absolute Minimum: 0.5 mL plasma
Rejection Criteria:
Heparinized specimens.
Turn Around Time:
3-5 days upon receipt at reference laboratory.
Reference Range:
By report.
Interpretive Data:
Hepatitis C viral RNA is tested using reverse-transcription polymerase chain reaction (RT-PCR) to amplify a specific portion of the 5' untranslated region (5' UTR) of the viral genome. The amplified nucleic acid is sequenced bi-directionally using dye-terminator chemistry (ABI). Sequencing data is compared to a database of characterized sequences.

Isolates of hepatitis C virus are grouped into six major genotypes (1-6). These genotypes are subtyped according to sequence characteristics. Due to high conservation of the 5' untranslated region of the HCV genome, this test has limitations in differentiating subtype 1a from 1b. Therefore, these subtypes will be reported as "1a or 1b." In rare instances, Type 6 virus may be misclassified as Type 1.
Comments:
Ordering Recommendation
Assay does not differentiate between type 1a and 1b, or between rare type 6 and type 1. Do not order prior to molecular confirmation of positive hepatitis C (HCV) screen.

This test may be unsuccessful if the HCV RNA viral load is less than log 3.6 or 4000 IU/mL.
Methodology:
Polymerase Chain Reaction/Sequencing
CPT Code:
87902