Human Leukocyte Antigen B*5701 allele (HLA-B*5701) Genotyping
Test Code
HLA-B*5701
CPT Codes
83898 x9 ; 83894 x2 ; 83912 x1 ; 83912-25 x1
Specimen
Whole blood or buccal swabs
Volume
5 mL of whole blood or four buccal swabs
Minimum Volume
3 mL of whole blood or four buccal swabs
Container
Lavender-stopper (EDTA) tube or paper envelope for dried buccal swabs
Storage Instructions
Maintain at room temperature or refrigerate
Cause for Rejection
Hemolyzed specimen; quantity not sufficient
Use
HLA-B is a human leukocyte antigen class I molecule which presents modified endogenous peptides to CD8+ T-cells to facilitate a cytotoxic immune response. The HLA-B*5701 allele has been shown to be strongly linked to risk of HSR (hypersensitivity reaction) to the antiretroviral drug, abacavir. Screening for the presence of this allele prior to initiation of abacavir-containing therapy can identify patients with an increased risk of experiencing an HSR. This test will determine the presence or absence of the HLA-B*5701 allele.
Limitations
A negative test result does not rule out the possibility that a patient could develop an abacavir HSR; physicians should continue to monitor patients accordingly.
Methodology
Polymerase chain reaction combined with agarose gel analysis.
Turnaround Time
Five business days after receipt of specimen. STAT turnaround time of 3 business days is available for an additional charge.
References
Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents. Department of Health and Human Services. January 29, 2008;1-128.
Mallal S et al. HLA-B*5701 screening for hypersensitivity to abacavir. N Engl J Med 2008;358(6):568-79. PREDICT-1 trial
Saag M et al. High sensitivity of human leukocyte antigen-b*5701 as a marker for immunologically confirmed abacavir hypersensitivity in white and black patients. Clin Inf Dis 2008;46(7):1111-8.
Almeida CA Cytokine profiling in abacavir hypersensitivity patients. Antivir Ther 2008;13(2):281-8.
Rauch A. et al. Prospective genetic screening decreases the incidence of abacavir hypersensitivity reactions in the Western Australian HIV cohort study. Clin Inf Dis 2006;43(1):99-102.
Martin AM et al. HLA-B*5701 typing by sequence-specific amplification: validation and comparison with sequence-based typing. Tissue Antigens 2005;65:571-574.
Hughes D et al. Cost effectiveness analysis of HLA-B*5701 genotyping in preventing abacavir hypersensitivity. Pharmacogenetics 2004;14:335-342.
Mallal S. et al. Association between presence of HLA-B*5701, HLA-DR7, and HLA-DQ3 and hypersensitivity to HIV-1 reverse-transcriptase inhibitor abacavir. Lancet 2002;359(9308):727-32.