Identify individuals at increased risk for statin-related muscle toxicity.
- Patient Preparation
- Lavender (EDTA) or pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Plasma or serum. Heparinized specimens.
- Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month
Characteristics: Simvastatin is a commonly prescribed hypolipidemic drug used for cholesterol reduction and control. Approximately 1-5 percent of exposed individuals may experience a dose-dependent myopathy (skeletal muscle toxicity). Symptoms may include pain, muscle weakness, and cramps. The organic anion transporter polypeptide 1B1, encoded by SLCO1B1, transports active simvastatin acid from the blood stream into the liver. This test detects a common variant that reduces the function of the transporter, resulting in an increased plasma concentration of the drug.
Inheritance: Autosomal co-dominant.
Cause: Simvastatin hypersensitivity reaction is strongly associated with the SLCO1B1*5 allele. The mechanism is related to changes in the activity of organic anion-transporter polypeptide 1B1 (OATP1B1).
Allele Tested: SLCO1B1*5 (rs4149056, c.521T>C).
Allele Frequency: Middle Eastern 5 percent, Caucasian 1-3 percent, African 0-2 percent,Asian 0-2 percent, Less than 1 percent in other populations.
Clinical Sensitivity: Drug-dependent.
Methodology: Polymerase Chain Reaction (PCR) and Fluorescence Monitoring.
Analytical Sensitivity and Specificity: Greater than 99 percent.
Limitations: Only the targeted SLCO1B1 variant will be detected. Diagnostic errors can occur due to rare sequence variations. Risk of therapeutic failure or adverse reactions with statins may be affected by genetic and non-genetic factors that are not detected by this test. This result does not replace the need for therapeutic or clinical monitoring.
|Component Test Code*||Component Chart Name||LOINC|
|2008427||Statin Sensitivity SLCO1B1, Specimen|
|2008428||Statin Sensitivity SLCO1B1,*5 Genotype|
- Simvastatin myotoxicity assay
- Statin-induced myopathy assay