Positive TB Skin Test 10 or 15mm?

Nurses General Nursing

Published

Timeline: Left work (a year ago)

One year later (aka 2018), got first step TB test = negative

Another week after, got second step TB test = supposedly positive (10mm)

I have not worked at a clinical setting since I quit a year ago and I have no other risk factors. With that said, should a positive skin test be 10mm or 15mm in my case? I understand that it's usually 10mm for healthcare workers, but I'm wondering if it'll be 15mm since I haven't worked at a high-risk setting since my last negative TB test.

Specializes in OB-Gyn/Primary Care/Ambulatory Leadership.

Fact Sheets | Testing & Diagnosis | Fact Sheet - Tuberculin Skin Testing | TB | CDC

From that page:

An induration of 10 or more millimeters is considered positive in -Recent immigrants (

-Injection drug users

-Residents and employees of high-risk congregate settings

-Mycobacteriology laboratory personnel

-Persons with clinical conditions that place them at high risk

-Children

- Infants, children, and adolescents exposed to adults in high-risk categories

Specializes in Psych ICU, addictions.

Per our TOS, we can't give medical advice. You would need to contact your PCP to follow-up on your results and to determine if in fact your test would be considered negative.

Remember that a positive TB test does not mean that you have active TB, but that you were exposed to it at some point...and that exposure doesn't necessarily have to have occurred in a clinical setting, or even in a high-risk setting.

Best of luck.

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