Identify individuals at increased risk for statin-related muscle toxicity.
Polymerase Chain Reaction/Fluorescence Monitoring
Lavender (EDTA) or pink (K2EDTA), or yellow (ACD Solution A or B).
Transport 3 mL whole blood. (Min: 1 mL)
Plasma or serum. Heparinized specimens.
Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month
Background Information for SLCO1B1, 1 Variant:
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). The *1 allele (normal transporter function) is presumed when the *5 allele is not detected. One copy of the *5 allele predicts decreased transporter function; two copies of the *5 allele predicts poor transporter function.
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.
Please note the information contained in this report does not contain medication recommendations, and should not be interpreted as recommending any specific medications. Any dosage adjustments or other changes to medications should be evaluated in consultation with a medical provider.
Laboratory Developed Test (LDT)
|Component Test Code*||Component Chart Name||LOINC|
|2008427||SLCO1B1, 1 Variant, Specimen|
|2008428||SLCO1B1, 1 Variant,*5 Genotype|
- Simvastatin myotoxicity assay
- Statin-induced myopathy assay