- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Abacavir sulfate is a nucleoside reverse transcriptase inhibitor (NRTI) used for the treatment of HIV.
Abacavir hypersensitivity reaction is characterized by fever, rash, malaise, gastrointestinal, and respiratory symptoms.
Symptoms typically appear within the first six weeks of treatment, worsen with each subsequent abacavir dose, and may be severe or fatal.
Incidence: HLA-B*5701 allele frequency varies by ethnicity: Indian 0.20, Thai 0.11, Caucasian 0.08, African American 0.02, Asian (rare).
Inheritance: Autosomal dominant.
Penetrance: 98 percent.
Cause: Abacavir hypersensitivity is strongly associated with the HLA-B*5701 allele. The mechanism is related to drug-specific activation of T lymphocyte killer cells.
Variant Tested: Single nucleotide polymorphism (SNP) rs2395029 in the HCP5 gene which is in linkage disequilibrium with HLA-B*5701.
Clinical Sensitivity and Specificity: 98 and 99 percent respectively, for immunologically confirmed hypersensitivity reaction.
Methodology: Polymerase Chain Reaction/High Resolution Melt Analysis.
Analytical Sensitivity and Specificity: 99 percent for prediction of HLA-B*5701 carrier status by SNP rs2395029 genotyping.
Limitations: Diagnostic errors can occur due to rare sequence variations. Rare recombination events between HCP5 SNP
rs2395029 and HLA-B*5701 may occur. Alleles other than HLA-B*5701 will not be evaluated. Non-genetic factors that may affect drug sensitivity are not identified.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
- Abacavir hypersensitivity genotyping
- Abacavir Sensitivity
- HLA-B 5701 Genotype, Abacavir Hypersensitivity, Saliva