TB? To test or not?

June 28, 2006 1:10 AM

Do I need to get a TB test?

One of my colleagues has recently been diagnosed with TB, and is now being treated for it. Should I get tested? I've had the immunization when I was younger. I'm working in Nepal if that makes any difference, and in an office environment, so am not in particularly close contact with the aforementioned colleague.

posted by MrC to health (16 comments total)

I would get the test. They jab some stuff into your forearm, then check the results later. If a relatively large bump forms, you've got TB and you will die. No, just kidding. You probably will not die, not if you get treatment. But do get the test. If one colleague has TB, maybe others have it and don't know yet. Maybe you.

Cornell University:

...Among infectious diseases, TB remains the leading killer in the world, with about 2-3 million TB-related deaths each year or more than 5000 deaths every day.

TB bacteria are spread through the air from one person to another when a person with active TB disease contaminates the air when they cough, laugh, talk, or sing. The infectious particles spread easily in close quarters and in poorly-ventilated spaces. People nearby may breathe in these bacteria and develop TB infection and disease. Many people who have TB infection never develop the TB disease. But the bacteria can become active and cause TB disease over time, becoming active decades after initial infection....

And there is a lot more information online about TB testing.
posted by pracowity at 3:40 AM on June 28, 2006 [1 favorite]

Most people have some degree of TB in their body. When you reach a certain threshhold, you're diagnosed with TB.

Why not get tested? Wouldn't it be better to know?

As I understand the immunization wears off.
posted by k8t at 4:15 AM on June 28, 2006

IANAD, but... my understanding about TB is that unless he live/works with someone with active TB, he probably didn't get it via the air, but instead got it from food - like unpasteurized dairy. If you didn't eat that food, there's a good chance you don't have TB, bc TB isn't the type of illness that is transmitted easily via the air - usually people get it through the air if they are repeatedly exposed. And unless he (or someone else in your office) has active TB, you can't catch it from working in close proximity with him.

Still, why not get tested? I've been tested several times - no biggie. Getting treated is a bit of a bummer - no alcohol for 9 months, I believe - but it can be treated quite successfully, so nothing to be afraid of.

Yes, it's relevant that you're in Nepal - higher % of cases than in some more developed countries, and more likely to be exposed to diseases via food. And the TB vaccine is not particularly reliable, so don't be reckless just bc you have had the vaccine.
posted by Amizu at 5:02 AM on June 28, 2006

I am using my husbands account, and don't really know if I am posting correctly. I just thought this link might help.
"Having had a previous BCG vaccination will affect a Mantoux test result: it is generally positive."
posted by Jaybo at 5:16 AM on June 28, 2006

You need to get tested.
There used to be only one kind of TB, and it wasn't particularly contagious (male relative worked in a 6 man office with a guy who had it for , they figured, 5 or 10 years when they found it, and nobody else had caught it) but now they have that new & improved antibiotic-resistant TB which spreads like wildfire.
/no idea how common that is in Nepal
posted by unrepentanthippie at 5:20 AM on June 28, 2006

Jaybo makes a good point; you can't get a reliable skin test after you have had the BCG vaccine for TB. If Nepal has some organization similar to our public health departments in the US, I would go there and follow their reccomendations. TB control is a major initiative of WHO and various national health agencies worldwide, so they have put a lot of effort into diagnosis, prevention, and treatment. You will probably need a chest X-ray and if it is positive, you can expect to be on a multi-antibiotic regimen for 6 months or a year. The anti-TB drugs are potentially toxic to your liver, so the advice is not to drink while you are taking them. Just an idea of what to expect if you are positive; TB is actually pretty hard to catch by casual contact if you have an intact immune system, though, so even if your co-worker has it, it is quite likely you do not.
posted by TedW at 6:07 AM on June 28, 2006

Looking again, I see that should read Mrs. Jaybo makes a good point...
posted by TedW at 6:07 AM on June 28, 2006

I've had the vaccine, too, so I always test positive (stupid antibodies). I'm not sure what kind of health infrastructure exists in Nepal. In the US, when you test positive you're subject to a chest X-ray to look for scarring.

If there's any scarring -- even if you have evidence (old chest X-rays) that it was caused by something else -- you'll be put on a six month anti-TB pill regimin.

If X-rays aren't available where you are, you might be put on the pills, too.

I don't recall the name of the pills I was given, but they had a high likelihood of causing liver damage. I had to go in for monthly blood tests until the TB treatment had run its course, and I was supposed to watch for signs of jaundice, too. If you're a big drinker, the liver issue could be pretty major. I didn't drink at all during my treatment.

It's really annoying, but TB is so nasty that it's probably worth it to go on the treatment. Depending on what country you're from, you might not be allowed back home otherwise. Australia would not issue me a visa until my treatment was complete, for example.
posted by croutonsupafreak at 6:55 AM on June 28, 2006

Absolutely do not get tested. Doctor's waiting rooms are cold and have really old magazines. They make you wait forever, and then they'll stick you with a needle. You don't need to put up with that just for a little peace of mind. You'll be fine.
posted by Terminal Verbosity at 7:29 AM on June 28, 2006

I'm from the UK but I now live in the US and, for various reasons, I've had to have two TB tests in the last three years. Some doctors respond differently to others when I tell them that I've had a BCG. The first one said that I definitely had TB and then sent me to be x-rayed. I was absolutley clear but the doctor recommended that I take the course of drugs andway just to make sure. I declined.

I just had another test a couple of weeks ago and the doctor spent some time in Britain. I had basically no reaction (like the first time) but he was aware of the BCG test so he said that I was fine. For the record the first doctor was a regular doctor and the second a government physician. I can't help feeling that the first doctor was full of shit and was trying to peddle (potentially) damaging drugs in order to make a buck for the pharmaceutical companies.
posted by ob at 7:32 AM on June 28, 2006

Having said all that, yes you should get tested, just remember to point out when you're being tested that you were immunized when you were young.
posted by ob at 7:48 AM on June 28, 2006

You will most likely test positive for 'latent TB infection.' This is not 'active TB disease.' You had the BCG, which wears off but will show positive years later, like every other person in this clinic. You are living in a region considered high risk for TB, so you very well might have been exposed, as TB is one of the three big airborne diseases.

Here in the US, particularly at my clinic, that would be 'low risk' and the docs wouldn't stick you on the regimen - you'd get a clear CXR and depending on the day and the individual doc, they'd either send you home or say, here, take these, come back in a few months, then you'll get a letter and never have to have a PPD again - but out in Nepal...well, things might be different. I don't know if they'd bother giving you the prophylactic meds.

Where I work, this is the regimen: Isoniazid 300 mg daily for 6-12 months depending on risk factor (usually 9), with 50 mg Vit. B6 for flavor and possibly Rifampin if it's high risk. You cannot drink the drinky-drinks and it might mess with your liver. If you have any pre-existing liver conditions, or start feeling funny, they'll check your LFTs.
posted by cobaltnine at 8:16 AM on June 28, 2006

I had the BCG vaccine about 25 years ago (I'm 26). As a child, the Mantoux test would always come back a resounding positive; however, I was just given a Mantoux test a few weeks ago that came back completely negative on the test and the false-negative retest. I was told that the BCG wears off over time.

So, I say, get tested, but be prepared for a "false" positive. And what ob said.
posted by penchant at 8:20 AM on June 28, 2006

The test is very straightforward, just go and get it. It's one shot on day 1, and a return visit about 10 days later where they look for a reaction.
I had to do it for work, and found out that my childhood immunization had worn off so they just gave me a new one during the second visit.
posted by easternblot at 9:06 AM on June 28, 2006

Aside from the problems with false negatives, it might be worth considering that by far the highest chance of developing active TB in an otherwise healthy person is within the first year after exposure. During that first year the chance of developing active disease is about 40%, and it declines quit noticeably and steadily after that.
posted by OmieWise at 11:35 AM on June 28, 2006

There is a LOT of misinformation and misconception in the answers here MrC. For example, the chance of developing active disease in the first year after exposure is NOT anywhere near 40%. Skin tests are NOT read on a return visit in 10 days. BCG vaccinations in childhood should NOT typically lead to false positives on skin testing as adults. Most people do NOT have some degree of TB in their body. TB is NOT usually passed on in food. The standards for TB testing and test interpretation are NOT the same in the US as they would be in Nepal, and depend entirely on disease prevalence among other factors.

Unfortunately there are just too many for me to correct in a reasonable amount of time. The answer to your question is probably quite nuanced actually and depends on a lot of factors which you haven't detailed, not the least of which are your access to health care in Nepal, your age, your degree of exposure, and your health history, and whether or not you are ill right now. Most importantly, you haven't differentiated whether your contact is being treated for 'active' or 'latent' TB infection, which will change everything. Really the best thing to do is head to a clinic in Kathmandu. Like maybe this place.
posted by drpynchon at 1:58 PM on June 28, 2006