Understanding Your Laboratory Test: What Patients Need to Know Before, During, and After Testing
This blood test checks for a specific genetic variant (Q141K) in the ABCG2 gene that affects how your body processes certain medications.
{"The ABCG2 Q141K test identifies a genetic variant that impacts drug metabolism","Results help doctors personalize medication dosing for drugs like statins","A simple blood sample is all that's needed for this genetic test","The variant is common and inherited from parents","Results guide safer and more effective medication choices"}
Key facts at a glance
- LOINC
- 104280-3
- Short code
- ABCG2 Q141K
- Synonyms
- ABCG2 gene.p.Q141K Bld/T Ql
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (purple-top) tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- molgen
- CPT
- 81403
- SNOMED
- 371510003
- Specimen volume
- 2-3 mL whole blood
- Stability
- Room temperature: 24-48 hours; Refrigerated (2-8°C): 5-7 days; Frozen (-20°C or below): acceptable for long-term storage
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 72–168 hours
- Order
- routine
This test is a laboratory procedure that helps your healthcare provider gather important information about your health. It is commonly ordered as part of a routine checkup or to investigate specific symptoms you may be experiencing.
The ABCG2 Q141K test is a genetic test that looks for a specific change (variant) in the ABCG2 gene, which provides instructions for making a protein called Breast Cancer Resistance Protein (BCRP). This protein acts as a drug pump, helping to move certain medications out of cells. The Q141K variant (sometimes written as p.Q141K or rs2231142) is a common genetic change that can affect how well this protein works.
The test is usually performed by a trained healthcare professional who collects a small sample, such as blood, urine, or tissue, depending on what your provider has ordered. The sample is then sent to a laboratory, where specialists analyze it and report the findings back to your doctor.
A healthcare provider will collect a small sample of your blood, usually from a vein in your arm. The sample is then sent to a laboratory where technicians analyze your DNA to determine whether you have the Q141K variant in the ABCG2 gene. The test looks for the presence or absence of this specific genetic change.
Your healthcare provider may recommend this test to screen for certain conditions, confirm or rule out a diagnosis, monitor an existing medical problem, or evaluate how well a current treatment is working for you over time.
Your doctor may order this test if you are starting or currently taking certain medications that are affected by the ABCG2 gene. These may include some cholesterol-lowering medications (statins like simvastatin), certain cancer chemotherapy drugs, and some other prescription medications. The test helps your doctor understand how your body processes these drugs and may influence dosing decisions.
Your results will show whether your measurements fall within the normal reference range established for this test. Values that are higher or lower than expected may point to a health concern, but only your healthcare provider can interpret them accurately in the context of your overall health and medical history.
The test result will typically indicate whether you have the Q141K variant (positive/present) or not (negative/absent). Having this variant can affect how your body handles certain medications. Your doctor will interpret these results in the context of your overall health and other medications you are taking to determine the most appropriate treatment approach.
Reference range
Result reported as Detected (variant present) or Not Detected (wild-type homozygous). Interpretation includes: Homozygous wild-type (CC), Heterozygous (CT), or Homozygous variant (TT) for the Q141K polymorphism.N/A
No special preparation required. Inform the laboratory of any recent blood transfusions, as this may affect results. Provide current medication list as certain drugs may influence testing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The ABCG2 Q141K variant is clinically significant because it can affect drug response and safety. Individuals with this variant may have reduced function of the BCRP protein, which can lead to higher drug levels in the body and increased risk of side effects. This is particularly important for certain statins (like simvastatin), where the variant may require dose adjustments. The variant is also relevant for some chemotherapy agents and other drugs. Pharmacogenetic testing like this helps enable personalized medicine approaches, allowing doctors to choose medications and doses that are more likely to be safe and effective based on individual genetic makeup.
Frequently asked questions
Is this test the same as genetic ancestry testing?
Will my insurance cover this test?
Do I need to fast before this test?
How long does it take to get results?
Will my children need this test?
Can the result of this test change over time?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy