CPT® Code 81328

SLCO1B1 (solute carrier organic anion transporter family, member 1B1) (eg, adverse drug reaction), gene analysis, common variant(s) (eg, *5)

The CPT® Code 81328 pertains to the gene analysis of the SLCO1B1 gene, which is part of the solute carrier organic anion transporter family. This analysis focuses on identifying common variants, such as the *5 variant, which can have significant implications for drug metabolism and the risk of adverse drug reactions. The SLCO1B1 gene plays a crucial role in encoding a liver-specific protein responsible for the transport of various molecules, including bilirubin, hormones, toxins, and a range of medications, particularly statins, antibiotics, and chemotherapy agents, to the liver for detoxification and elimination from the body. This gene is situated on the short (p) arm of chromosome 12 at position 12.1. The most prevalent variant of this gene involves a substitution where the amino acid valine at position 174 is replaced by alanine, denoted as V174A or SLCO1B1*5. This specific variant is notably associated with an increased risk of statin-induced myopathy, a condition characterized by muscle pain, weakness, and cramping. The analysis of this gene can help determine an individual's risk for experiencing adverse reactions to statins based on their genetic makeup. For instance, individuals with two valine alleles (T/T) typically exhibit normal protein function and a very low risk for adverse drug reactions. In contrast, those with a valine/alanine genotype (T/C) may experience decreased drug metabolism, placing them at a higher risk for statin-induced myopathy. Furthermore, individuals with the alanine/alanine genotype (C/C) show markedly decreased drug metabolism and are at a significantly elevated risk for this condition. The identification of these genetic variants through testing can guide healthcare providers in selecting the most appropriate statin medication and dosage for patients, as well as in monitoring potential side effects. The testing process involves obtaining a blood sample, which is analyzed using real-time polymerase chain reaction (RT-PCR) techniques to detect the presence of these genetic variants.