TB Skin Test
 

Why wife and I moved here on H1B/H4 visas last year and are now filing for adjustment of status. We have had the medical exam by a civil surgeon here in SF, and had appropriate vaccinations and the TB skin test done. We are now about 40 hours in since the test and to my eyes it looks positive - red and puffy - on both of us. We were both BCG vaccinated in our teens and would assume very low risk.

I hadn't realised at the time that BCG vaccination had any effect, else I would have gone for the blood test. It looks like this result will mean referral for treatment, even with a clear chest xray (which from what I have read, will come next).

Has anyone had any experience with this? Particularly in California?

Nothing ever seems to be simple!

Thanks

Re: TB Skin Test
 

This happened to a friend, she had to have the chest xray done which was clear and that was that. We are in TX where the authorities are very careful about TB.

Re: TB Skin Test
 

BCG vaccine causes false positives to the skin test subsequently. When I applied for a green card, the doctor didn't even bother with a skin test and just sent me for an X-ray instead.

Re: TB Skin Test
 

Skin tests show positive if you've ever had TB, not necessarily that you have current active TB.

Re: TB Skin Test
 

Yes this happened to me - I just got an x-ray later that day and it delayed the medical results by 3 days. The doctor says happens to a lot of Europeans who have been vaccinated.

Re: TB Skin Test
 

Wow. I missed my BCG in my teen days as I was absent for the "six pricks". Thankfully I walked my skin test, good to know that it can cause false positives though.

Re: TB Skin Test
 

We had a new immune-assay test when we presented for our medicals. There is a method which uses part of the blood test to test for immunity caused by the vaccination.

Interferon Gamma release assay was the name.

Re: TB Skin Test
 

Same, due to vaccine, sent for X-ray to receive all clear.

Re: TB Skin Test
 

Same happened for me, well I did not at the time realise what it was for, and was told I was positive.

Pointed out that they had not X Ray'd so how could they tell and suddenly you could see the light bulb go on.

Re: TB Skin Test
 

Wife had same issue in California, just did X-Ray and that was accepted.

Re: TB Skin Test
 

You need more than redness to have a positive skin test. The reaction should be measured in millimeters of the induration (this is the palpable, raised, hardened area or swelling, you can feel this as you run your fingers over the area). The reader will not measure just redness. The diameter of the raised area should be measured across the forearm. For a positive test in an immigrant per the CDC, the raised area must measure 10mm or >. You can check the CDC website for additional info. Be sure to get the skin test read within the 48-72 hour window.
If your test is positive there some controversy about whether the BCG can cause a positive result. I have had this issue for thirty years! Now there is some doubt about the reliability of the Interferon-Gamma Release Assays because of many false positives. I just get a chest x-ray every so often.

Re: TB Skin Test
 

When you go to work in the education system in the US you have to have a TB skin test and false positives also happen a lot.

Just means they will send you to a chest x-ray if there is any doubt, and some places just go straight to the chest x-ray now and skip the skin test, like the earlier poster said.

Even if you are actually positive - it's not the end of the road. Latent TB infection is not a show-stopper for visas; inactive TB cannot be spread to someone else and won't make you sick, but there are extra steps/requirements for visas and local health departments etc. I can't recall exactly what. Latent TB can of course become active - but that is a possibility not a certainty.

It's not a disease that spreads through casual contact, someone has to be symptomatic with active TB, and then it spreads through the air.

Re: TB Skin Test
 

Which is of course why the new test has become available. It added $50 to our blood tests IIRC

Re: TB Skin Test
 

If you had the BCG it's a false positive: I did the qantiferon TB test instead so you can probably ask to do that instead of an xray - whichever is cheaper.

Re: TB Skin Test
 

I had the BCG as a child and got a negative result from the skin test as part of my green card medical (twice in fact, as due to processing times the first medical expired) - so it doesn't always result in a false positive.

Red puffiness is fine - per DebzinUS above, it is the size of the hard raised area that determines whether the result is interpreted as a positive or negative reaction.

https://www.cdc.gov/tb/topic/testing/tbtesttypes.htm