Can anyone say if a history of TB (5 years ago) might pose a problem for the medical exam for a US visa for a Thai girl?

TB? Usually not a large problem. If currently "active" may delay things for six months or so while receiving treatment. "Inactive" or "non-communicable" TB is usually OK for a visa.

Note, I assume you're talking about an Immigrant Visa IV for which a med exam is mandatory. If talking about a Tourist Visa/Non-Immigrant, NIV, there is no medical exam required.

Mac

http://travel.state.gov/content/visas/english/immigrate/immigrant-process/interview/prepare/medical-exam-faqs.html

Applicants with a previous positive skin test for tuberculosis should provide a certificate from the attending doctor (giving the circumstances of the positive test result, and indicating any treatment prescribed, and its duration) to the panel physician. If the applicant has ever been diagnosed with tuberculosis, the applicant must present a written certification, signed by the attending doctor, proving that the applicant was adequately treated. The certificate must include dates and types of medications taken. Applicants who ever had an abnormal chest X-ray should borrow the last X-ray films taken and bring them to the panel physician. The actual films, not the typed reports, may be required to compare with the X-rays that will be taken at the medical examination.

What if the applicant had a positive tuberculosis skin test?

http://wwwnc.cdc.gov/travel/yellowbook/2014/chapter-9-health-considerations-for-newly-arrived/before-arrival-in-the-united-states-the-overseas-medical-examination

TB? Usually not a large problem. If currently "active" may delay things for six months or so while receiving treatment. "Inactive" or "non-communicable" TB is usually OK for a visa.

Note, I assume you're talking about an Immigrant Visa IV for which a med exam is mandatory. If talking about a Tourist Visa/Non-Immigrant, NIV, there is no medical exam required.

Mac

http://travel.state.gov/content/visas/english/immigrate/immigrant-process/interview/prepare/medical-exam-faqs.html

Applicants with a previous positive skin test for tuberculosis should provide a certificate from the attending doctor (giving the circumstances of the positive test result, and indicating any treatment prescribed, and its duration) to the panel physician. If the applicant has ever been diagnosed with tuberculosis, the applicant must present a written certification, signed by the attending doctor, proving that the applicant was adequately treated. The certificate must include dates and types of medications taken. Applicants who ever had an abnormal chest X-ray should borrow the last X-ray films taken and bring them to the panel physician. The actual films, not the typed reports, may be required to compare with the X-rays that will be taken at the medical examination.

What if the applicant had a positive tuberculosis skin test?

http://wwwnc.cdc.gov/travel/yellowbook/2014/chapter-9-health-considerations-for-newly-arrived/before-arrival-in-the-united-states-the-overseas-medical-examination

Thanks, perfect. The link was the missing piece for me.

Often those exposed to TB but never develop clinical problems and those who had full blown TB appear the same- at initial, cost effective testing. Basically, your body reveals in it's library that it's been exposed. Next most cost effective step is chest X-ray. If someone, green card applicant, for example, is positive for exposure and can produce no documentation I believe they require a lengthy regimen of rifampin isoniazid and ethambutol, while in USA. (The drugs may hv changed).

I base this on my buddies fiancé coming to USA/green card. I don't recall details but recall looking it up and finding this practice fairly widespread for those coming to USA with such TB exposure. I suspect, later, the us doc confirms compliance. You don't want to take those meds again even prophylacticaly if you hv already cleared. They're quite strong Rx.

I hope you can get med clearance. Anticipate being asked and try hunt the docs now.

Often those exposed to TB but never develop clinical problems and those who had full blown TB appear the same- at initial, cost effective testing. Basically, your body reveals in it's library that it's been exposed. Next most cost effective step is chest X-ray. If someone, green card applicant, for example, is positive for exposure and can produce no documentation I believe they require a lengthy regimen of rifampin isoniazid and ethambutol, while in USA. (The drugs may hv changed).

I base this on my buddies fiancé coming to USA/green card. I don't recall details but recall looking it up and finding this practice fairly widespread for those coming to USA with such TB exposure. I suspect, later, the us doc confirms compliance. You don't want to take those meds again even prophylacticaly if you hv already cleared. They're quite strong Rx.

I hope you can get med clearance. Anticipate being asked and try hunt the docs now.

Does not apply to people (like the one referenced in the OP) who have already been successfully treated for TB.

Often those exposed to TB but never develop clinical problems and those who had full blown TB appear the same- at initial, cost effective testing. Basically, your body reveals in it's library that it's been exposed. Next most cost effective step is chest X-ray. If someone, green card applicant, for example, is positive for exposure and can produce no documentation I believe they require a lengthy regimen of rifampin isoniazid and ethambutol, while in USA. (The drugs may hv changed).

I base this on my buddies fiancé coming to USA/green card. I don't recall details but recall looking it up and finding this practice fairly widespread for those coming to USA with such TB exposure. I suspect, later, the us doc confirms compliance. You don't want to take those meds again even prophylacticaly if you hv already cleared. They're quite strong Rx.

I hope you can get med clearance. Anticipate being asked and try hunt the docs now.

Does not apply to people (like the one referenced in the OP) who have already been successfully treated for TB.

After reviewing my post and consulting with two others who are also doctors, I can't see what "does not apply" regarding my post. If you refer to consular affairs regarding visa versus green card, very well. Medically, it is a correct post. Being "successfully treated" for active TB does not change 'initial' detection test results later: it does not make things go bye bye on screenings. The test detects exposure. Treated or not, the patient has still been exposed. The pt requires proof of compliant treatment to avoid a requirement to "treat" the confirmed positive. The patient needs the "doc[uments] from his docs now to aid his paperwork.

In the absence of any demonstrable proof of complaint treatment and resolution the patient will have to either take a Treatment Regime again or confirm he is not active TB via additional labs looking at antibodies.