Last Updated 1 June 2025
Skin Test in India: A Complete Guide to Allergy, TB & Biopsy Tests
Experiencing an unexplained rash, persistent itching, or concerned about a new spot on your skin? A skin test is a vital diagnostic tool used to get clear answers. It uses your skin's reaction to identify a wide range of conditions. This guide will explain the most common types of skin tests in India, including for allergies, tuberculosis (TB), and skin biopsies, covering their purpose, procedure, cost, and results.
What is a Skin Test?
A skin test is a broad term for several medical procedures that involve applying a substance to the skin or taking a small skin sample to diagnose or screen for a condition. Instead of one single test, it refers to a category of tests, each with a unique purpose.
The three most common medical skin tests are:
- Skin Allergy Test: To identify allergens causing reactions.
- Tuberculin (TB) Skin Test: To screen for tuberculosis infection.
- Skin Biopsy Test: To diagnose skin cancers and other skin disorders.
Why is a Skin Test Done?
A doctor may recommend a specific skin test based on your symptoms and medical history. Here’s a breakdown of the main types and their purposes.
Skin Allergy Test (Prick & Patch Test)
If you suffer from symptoms like sneezing, rashes, hives, or digestive issues, a skin allergy test can pinpoint the trigger.
Purpose: To identify specific allergens (pollen, dust mites, food, pet dander, insect stings) that cause an immediate allergic reaction (skin prick test) or delayed reactions (skin patch test). Common Tests: The skin prick test is most common for airborne and food allergies. A skin patch test is used for contact dermatitis (e.g., allergies to metals, fragrances, or chemicals).
Tuberculin Skin Test (TB Skin Test / Mantoux Test)
This is a standard screening test for tuberculosis.
Purpose: The TB skin test (also known as the Mantoux tuberculin skin test or PPD skin test) is done to determine if you have ever been exposed to the bacteria that cause tuberculosis. Why it's done: It is often required for healthcare workers, for immigration purposes, or if you have been in close contact with someone who has active TB disease.
Skin Biopsy Test
A skin biopsy test is performed when a mole, spot, or rash looks suspicious.
Purpose: To diagnose or rule out conditions like skin cancer, fungal or bacterial infections, and inflammatory skin disorders like psoriasis. How it works: A pathologist examines the skin cells under a microscope to make a definitive diagnosis.
The Skin Test Procedure: What to Expect
The skin test procedure varies significantly depending on the type of test being performed.
For a Skin Allergy Test
Preparation: You'll need to stop taking antihistamines 3-7 days before the test. Procedure: In a skin prick test, a nurse places tiny drops of various allergens on your forearm and lightly pricks the skin under each drop. For a patch test, patches containing allergens are taped to your back for 48 hours. The procedure is not painful but may cause mild, temporary itching.
For a TB Skin Test
Procedure (Visit 1): A small amount of tuberculin fluid is injected just under the skin of your forearm, creating a small bubble. Procedure (Visit 2): You must return to the clinic 48 to 72 hours later so a healthcare professional can read the reaction on your arm. This second visit is mandatory for a valid result.
For a Skin Biopsy Test
Preparation: No major preparation is needed. Procedure: The area is numbed with a local anaesthetic. The doctor then removes a small piece of skin using a blade (shave biopsy) or a circular tool (punch biopsy). You may require a stitch or two. This is a clinical procedure and cannot be done via home collection.
Understanding Your Skin Test Results & Normal Range
Disclaimer: All skin test results must be interpreted by a qualified doctor in the context of your overall health and symptoms.
Skin Allergy Test Results
How to Read: For a skin prick test, a positive result is an itchy, red, raised bump (called a wheal) that appears within 15-20 minutes. The size of the wheal helps determine the severity of the allergy. Your report will often include an allergy skin test results chart.
TB Skin Test Results
How to Read: A positive tb skin test is determined by the size of the firm, hard, raised bump (induration), NOT the redness. A bump of 5mm or more can be positive for high-risk individuals, while a 15mm bump is considered positive for people with no known risk factors. A negative tb skin test has no bump or a very small one.
Skin Biopsy Results
How to Read: The results come in a pathology report. It will state if the cells are benign (non-cancerous), malignant (cancerous), or indicate another specific skin condition. It can take several days to a week to receive these results.
Skin Test Cost in India
The skin test cost in India depends heavily on the type of test, the city (e.g., Mumbai, Delhi, Bangalore), and the facility.
- Skin Allergy Test Price: A skin prick test cost in India can range from ₹3,000 to ₹10,000, depending on the number of allergens tested.
- TB Skin Test Price: This is a relatively inexpensive test, typically costing between ₹300 and ₹800.
- Skin Biopsy Test Cost: The skin biopsy test price can vary from ₹2,000 to ₹7,000, including the procedure and the histopathology report.
Next Steps: After Your Skin Test
Your results will guide what happens next.
- For Allergies: If positive, the next step is allergen avoidance, and your doctor may prescribe medications or recommend immunotherapy.
- For a Positive TB Test: This means you've been exposed to TB bacteria, not that you have an active infection. Your doctor will order a chest X-ray to check for active disease.
- For a Skin Biopsy: Depending on the results, your doctor will discuss treatment options, which could range from simple monitoring to medication or surgical removal of a lesion.
Frequently Asked Questions (FAQ)
1. What is the main purpose of a skin test?
The main purpose is to diagnose a condition by observing the skin's reaction to a substance or by examining a small sample of skin cells. This helps identify allergies, screen for TB exposure, and diagnose skin cancers or infections.
2. How painful is a skin prick test?
A skin prick test is generally not painful. The devices used only scratch the very top layer of the skin. Most people feel a mild, temporary pricking sensation, followed by some itching if they have a positive reaction.
3. What does a positive TB skin test look like?
A positive tb skin test is a firm, dense, raised bump (induration) at the injection site. The size of this bump, not the redness, determines the result. Seeing a positive tb skin test image online can help, but a professional must measure it for an accurate diagnosis.
4. How long does it take to get skin biopsy results?
It typically takes 5 to 10 days to receive the results from a skin biopsy test, as a pathologist needs to carefully process and examine the tissue sample.
5. Can I do a skin allergy test at home?
While some companies offer at-home allergy testing kits (usually blood tests), a clinical skin allergy test must be performed by a healthcare professional to ensure safety and accuracy, as a severe reaction, though rare, is possible.
6. What is the difference between a skin test and a blood test for allergies?
A skin test for allergy checks for an allergic reaction directly on the skin, providing quick results. A blood test for skin allergy measures the amount of specific IgE antibodies in your blood. Blood tests are a good alternative if you cannot stop taking antihistamines or have a severe skin condition.
Note:
This information is for educational purposes only and is not a substitute for professional medical advice. Please consult a licensed physician for health concerns or diagnoses.