How to diagnose Tuberculosis?

Q: The reports of my child are as follows: Erythrocyte sedimentation rate-15 mm (1 h), Elisa for Mycobacterium - IgG negative (160 Ser units), IgM positive(1.552O D units). The child is 19 months old and her weight is 10 kg which is same as was when she was 9 months old. The attending doctor has a doubt that she is suffering from T.B. Kindly confirm. The child is active.

A:Tuberculosis is usually readily diagnosed from symptoms (such as fever, cough, unusual sweating, diarrhea, mental changes) or findings (eg, chest X-rays, CAT scan of chest, brain, joints, abdomen) or examination of fluid from chest or lungs, urine, spinal fluid. A PPD skin test is usually positive, but would be unreliable if BCG vaccination had been given. The serum tests described are very sensitive, but they may not correlate with active disease; thus, they cannot be relied on in the absence of clinical disease. When TB is a strong possibility but infection cannot be proved, there are three possible courses of action: 1. Wait a few weeks to give the disease an opportunity to become clearly evident; 2. Treat for active disease for several weeks and re-assess; 3. Give prophylactic treatment with Isoniazid. If the patient is definitely ill and TB is very likely, option #2 is best.