Not true about lepromine test is –
**Core Concept**
The lepromine test, also known as the Mitsuda test, is a diagnostic tool used in leprosy to assess the patient's immune response against the leprosy bacillus (Mycobacterium leprae). It involves injecting a small amount of inactivated leprosy bacillus into the skin, and the resulting immune response is evaluated to determine the patient's disease status.
**Why the Correct Answer is Right**
The lepromine test is a measure of cellular immunity, specifically the delayed-type hypersensitivity reaction, which is an essential component of the immune response against M. leprae. When the test is performed, the patient's immune cells, such as T lymphocytes, recognize the inactivated leprosy bacillus and mount a response, leading to inflammation and a skin reaction at the injection site. This reaction is a sign of a healthy immune response and is typically seen in patients with a high degree of immunity to leprosy.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as the lepromine test is indeed a measure of cellular immunity, and it is used to assess the patient's immune response against M. leprae.
**Option B:** This option is incorrect as the lepromine test is not a blood test; it involves injecting a substance into the skin to assess the immune response.
**Option C:** This option is incorrect as the lepromine test is not used to diagnose other diseases; it is specifically used to diagnose leprosy.
**Option D:** This option is incorrect as the lepromine test is not a definitive diagnostic tool; it is used in conjunction with other diagnostic methods, such as clinical evaluation and bacteriological examination, to diagnose leprosy.
**Clinical Pearl / High-Yield Fact**
The lepromine test is an important tool in leprosy diagnosis, but it has limitations. A negative result does not rule out leprosy, and a positive result does not confirm the diagnosis. Therefore, it is essential to use the test in conjunction with other diagnostic methods to arrive at a accurate diagnosis.
**Correct Answer: B. The lepromine test is a skin test.**