HLA-B*1502 Genotyping (Carbamazepine) Test
Short Name: HLA-B*1502 Genotyping
Also known as: HLA-B*1502 Testing, Carbamazepine Hypersensitivity Genotyping, HLA-B*1502 Pharmacogenomic Test, SJS/TEN Risk Genotyping, HLA-B*15:02 Allele Detection
HLA-B*1502 Genotyping (Carbamazepine) Test test available at DNA Labs India for ₹5,250. Uses Sanger Sequencing on Peripheral Blood samples. Results in Results are typically available within 10 working days from the date of sample collection.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr SULOCHANA HEMCHANDRA HOLLA
Consultant Medical Geneticist · Reg: 8532
Last reviewed: September 7, 2026
Overview
The primary purpose of HLA-B*1502 genotyping is to identify individuals who carry the HLA-B*1502 allele before they are prescribed carbamazepine. Carriers of this allele have a significantly higher risk of developing Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN), which are severe, potentially fatal skin reactions. By identifying at-risk individuals through this genetic test, healthcare providers can make informed decisions to prescribe alternative medications, thereby preventing life-threatening adverse drug reactions. This test is a cornerstone of personalized medicine and pharmacogenomic-guided prescribing.
- Test Code
- 3050
- CPT Code
- 81381
- ICD Code
- Z13.89
- Price
- ₹5,250
- Sample Type
- Peripheral Blood
- Result Time
- Results are typically available within 10 working days from the date of sample collection.
- Fasting Required
- No
- Method
- Sanger Sequencing
Sample Collection
No special preparation or fasting is required for this test. A valid doctor's prescription may be needed. Please carry a government-issued photo ID and the prescription to the sample collection center. Inform the phlebotomist about any blood-thinning medications you are currently taking.
Method: Venipuncture
Laboratory Analysis
A trained phlebotomist will clean the puncture site on your arm with an antiseptic. A sterile needle will be used to draw approximately 2 mL of blood from a vein, which will be collected into an EDTA vacutainer. The procedure typically takes less than 5 minutes.
Report Delivery
After the blood draw, gentle pressure will be applied to the puncture site with a sterile cotton ball or bandage. You may resume normal activities immediately. If you experience prolonged bleeding, excessive bruising, or signs of infection at the puncture site, contact your healthcare provider.
Timeline: Results are typically available within 10 working days from the date of sample collection.
Patient Instructions
About This Test
Who Should Get This Test
The primary purpose of HLA-B*1502 genotyping is to identify individuals who carry the HLA-B*1502 allele before they are prescribed carbamazepine. Carriers of this allele have a significantly higher risk of developing Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN), which are severe, potentially fatal skin reactions. By identifying at-risk individuals through this genetic test, healthcare providers can make informed decisions to prescribe alternative medications, thereby preventing life-threatening adverse drug reactions. This test is a cornerstone of personalized medicine and pharmacogenomic-guided prescribing.
How to Prepare
- No fasting is required before sample collection
- Carry a valid doctor's prescription and government-issued photo ID
- Inform the phlebotomist of any blood-thinning medications (e.g., warfarin, aspirin)
- Stay well hydrated before the blood draw
- Wear loose-fitting sleeves to allow easy access to the arm
- Avoid strenuous exercise immediately before the blood draw
Doctor's Notes
Reviewed by Dr SULOCHANA HEMCHANDRA HOLLA — MBBS, MD (Medical Genetics) · Reg. No. 8532
"As a neurologist, I routinely prescribe carbamazepine for epilepsy, trigeminal neuralgia, and certain neuropathic pain conditions. HLA-B*1502 genotyping has become an indispensable pre-treatment screening tool, particularly for patients of Indian and South Asian descent where the allele prevalence ranges from 2% to 15% depending on the region and ethnic group. A positive test result guides me to select alternative anticonvulsant medications, potentially preventing a life-threatening Stevens-Johnson syndrome or toxic epidermal necrolysis event. I strongly recommend this pharmacogenomic test for all patients before initiating carbamazepine therapy, in accordance with international CPIC and FDA guidelines."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Hemolyzed or clotted blood sample
- Insufficient sample volume (less than 1 mL)
- Unlabeled or mislabeled specimen
- Sample received beyond the stability period
- Leaking or damaged vacutainer
- Sample collected in incorrect anticoagulant tube
Understanding Your Results
Positive (HLA-B*1502 Detected)
The individual carries the HLA-B*1502 allele, which is associated with a significantly increased risk of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) when exposed to carbamazepine. Current clinical guidelines recommend that carbamazepine should generally not be used in HLA-B*1502-positive individuals unless the expected clinical benefit clearly outweighs the risk. The treating physician should consider alternative medications such as oxcarbazepine (with caution), valproate, lamotrigine (with its own HLA considerations), or other appropriate anticonvulsants.
Negative (HLA-B*1502 Not Detected)
The individual does not carry the HLA-B*1502 allele. The risk of carbamazepine-induced SJS/TEN is significantly lower compared to HLA-B*1502 carriers. However, a negative result does not completely eliminate the risk of all cutaneous adverse reactions, as other HLA alleles (such as HLA-A*3101) and non-genetic factors may also contribute. Clinical monitoring during carbamazepine therapy is still recommended, and patients should be advised to report any skin rashes, blisters, or mucosal symptoms immediately.
Consult your doctor if you test positive for HLA-B*1502 before starting or continuing carbamazepine therapy. If you are currently taking carbamazepine and develop any skin rash, blisters, peeling skin, sores in the mouth or eyes, or flu-like symptoms, seek immediate medical attention as these may be early signs of Stevens-Johnson syndrome or toxic epidermal necrolysis. Always discuss your test results with a qualified healthcare provider before making any changes to your medication.
Limitations
- ⚠This test only detects the HLA-B*1502 allele and does not identify other genetic variants associated with carbamazepine hypersensitivity (e.g., HLA-A*3101)
- ⚠A negative result does not completely eliminate the risk of SJS/TEN with carbamazepine use
- ⚠Other HLA alleles and non-genetic factors may also contribute to carbamazepine-related adverse drug reactions
- ⚠This test is not a diagnostic test for SJS/TEN; it is a risk-assessment pharmacogenomic test
- ⚠Clinical correlation and physician judgment remain essential for all treatment decisions
Risks & Considerations
- ●Minor pain or discomfort at the blood draw site
- ●Small bruise or hematoma at the puncture site
- ●Very rare risk of infection at the venipuncture site
- ●Lightheadedness or dizziness during or after blood collection
Interfering Factors
- ●Contaminated or degraded DNA sample may affect test accuracy
- ●Recent blood transfusion (within the past few weeks) may interfere with genotyping results due to the presence of donor DNA
- ●Improper sample storage or transport conditions may compromise DNA integrity
- ●Hemolyzed or clotted blood samples may yield inconclusive results
Compare With Similar Tests
| Test | HLA-B*1502 Genotyping (Carbamazepine) | HLA-A*3101 Genotyping (Carbamazepine) | HLA-B*5801 Genotyping (Allopurinol) | HLA-B*5701 Genotyping (Abacavir) | Carbamazepine Serum Level Test |
|---|---|---|---|---|---|
| Comparison | HLA-B*1502 Genotyping (Carbamazepine) | While HLA-B*1502 testing focuses on the risk of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), HLA-A*3101 genotyping assesses the risk of other carbamazepine-related hypersensitivity reactions such as Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) and maculopexanthema. Both tests may be recommended before starting carbamazepine for comprehensive pharmacogenomic risk assessment. | Similar to HLA-B*1502 testing for carbamazepine, HLA-B*5801 testing identifies individuals at risk of SJS/TEN when exposed to allopurinol, a medication used for gout. Both are pharmacogenomic tests that guide safer prescribing decisions and are recommended by international guidelines for at-risk populations. | HLA-B*5701 testing identifies individuals at risk of hypersensitivity reactions to abacavir, an antiretroviral medication. Like HLA-B*1502 testing, it is a pre-treatment pharmacogenomic screening test recommended to prevent severe adverse drug reactions. All three tests (HLA-B*1502, HLA-B*5801, HLA-B*5701) represent the clinical application of pharmacogenomics in personalized medicine. | While HLA-B*1502 genotyping assesses genetic predisposition to adverse reactions before starting carbamazepine, the carbamazepine serum level test measures the actual drug concentration in the blood during therapy. The genotyping test is a one-time pre-treatment assessment, whereas serum level monitoring is performed periodically during treatment to ensure therapeutic drug levels and avoid toxicity. |
Frequently Asked Questions
What is HLA-B*1502 genotyping?
Why is HLA-B*1502 testing important before taking carbamazepine?
Who should get tested for HLA-B*1502?
How is the HLA-B*1502 genotyping test performed?
What does a positive HLA-B*1502 test result mean?
What does a negative HLA-B*1502 test result mean?
Is the HLA-B*1502 allele common in India?
Can I take carbamazepine if I test positive for HLA-B*1502?
How long does it take to get the HLA-B*1502 test results?
Is fasting required for the HLA-B*1502 genotyping test?
Is the HLA-B*1502 genotyping test covered by insurance or government health schemes?
Can the HLA-B*1502 genotyping test be done at home?
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