Quantiferon positive but no TB scars on Lungs

sputum test is also negative

You'll probably need to show proof of your past treatment and that you're healthy now. Get a letter from your doctor about your positive test being from past exposure.

Thankyou sir much appreciated

One last query- Should I disclose my Abdominal knox/TB case to the medical officer myself?

Because as per the law and my understating they are more concern about lung tuberculosis and in my case I never had it before.

Tuberculosis

Tuberculosis examination is limited to lung tuberculosis only where all new applicants will be subjected to the examination of lung tuberculosis and the cases where the result of the test indicates they have an ancient pulmonary or active tuberculosis will be deemed unfit healthy and will not be granted residence visa.

Tuberculosis screening is for all residents renewing their residence visa and if the existence of an ancient or active pulmonary tuberculosis persists, the person in such case will be medically fit.

But in this case, the person will be subjected to a follow-up by the department of preventive medicine or equivalent in government health bodies.

Look, to keep it very simple, if your chest X-ray is normal then there is NOTHING to worry about.  Quant is NOT a test during the UAE medical fitness exam, even as a confirmatory test (they do sputum / skin test) after an abnormal X-ray.

Quant is only recommended (by me on these forums) if your X-ray is abnormal.  In that case if your Quant is negative, you can show it to a doctor at the medical fitness center BEFORE they issue any judgement to try to sway your case - no guarantee though.

Thankyou brother for your message- just a quick query due to Intestinal TB I had abdominal surgery at that time and post surgery marks are very visible so I am confused they will definitely ask about it. so what to answer should I disclose my case honestly to them or what?

You are over thinking it.  If they ask, just say you had surgery due to intestine issues.  In all probability, they won't ask anything if lungs are clear - these are government doctors i.e. overworked, they don't have the time or inclination to discuss patient history in detail especially if there are no problems highlighted in the visa medical.