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Doctor insights on: What Does A Negative Tb Test Result Look Like

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Positive test result for TB my husband got a job offer and had to get a TB test. He went back to get the results and the spot is slightly red and barely over 10 mm. He is convinced that the results are positive and as a result he won't get the job. The

Positive test result for TB my husband got a job offer and had to get a TB test. He went back to get the results and the spot is slightly red and barely over 10 mm. He is convinced that the results are positive and as a result he won't get the job. The

Hello.: Hello. You can have an overlying are of redness, that doesn't mean the test is positive. I always used the ball point pen method to read the TB test. You gently move the pen back and forth to determine where there is underlying induration. Being PPD positive and having tuberculosis are two very different things. Please have him talk to the person who administered the test to find out the result. You are checking for inducation and not color. Take care. ...Read more

Dr. Scott Lindquist
615 Doctors shared insights

Mycobacterium Tuberculosis Infection (Definition)

Mycobacterium tuberculosis is an infectious organism that spreads by droplets coughed out by an infected person. Infection is established initially in lungs, but can spread within lungs & to other body parts, or can become latent, with reactivation occurring years to decades later. With effective treatment, it can be completely eliminated although drug resistant ...Read more


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What does a negative TB test look like?

Doc: Either your blood test igra is negative or your skin testing does not show any "bump". This should always be checked by a professional since even health care workers report false results. Best to check with a doc and not pa or np or nurse. ...Read more

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What do a positive and negative TB test look like?

TB Tests: I bet you could google image that question. A positive reaction is read after 48 hours from the test. It would be a raised redness greater than 5 mm in circumference. ...Read more

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Tb skin test negative, quentform TB test negative, bone marrow biopsy results indicative of TB (reacts to ziehl niehlssen), PCR negative. How come?

No...actually: The zn stain is a broad stain for acid fast bacilli of which mycobacterium tuberculosis is one of many. The specific tests like quantiferon or the pcr test are against you having tb. The culture is the "gold standard" but you will need to wait for it. It might turn out be a cousin of TB and that too will grow out of culture. Stay on TB meds until they are certain of the AFB positive organism. ...Read more

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What should my skin look like after taking a TB test?

What should my skin look like after taking a TB test?

See below: A positive PPD is determined by the presence of swelling (induration) around the injection site. Little or no swelling indicates a negative test. Reddness is not used to determine a neg or pos test. ...Read more

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What does a + TB test look like?

What does a + TB test look like?

Positive PPD test: A positive TB test should look like hard, raised bump with size >5to15 mm depending of the risk category you are in. It should be read in between 48 to72 hours. It is the hardness and not redness which is read. Thanks. ...Read more

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What does a positive TB test look like?

What does a positive TB test look like?

Skin test: If you had a PPD skin test and you have no risk factors, a positive test is when after 48 to 72 hoursyou have swelling in the site and redness that measures more than 15 mm, it is considered a positive tb. Test. ...Read more

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What does a positive TB test look like? How is this treated?

What does a positive TB test look like? How is this treated?

What is important: Is what it feels like - not how it looks. Induration is palpated & measured. Treatment (such as INH) is determined once it is established where this is latent or active TB and the type. ...Read more

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What do positive TB test results mean? How should I interpret the positive result of a TB test?

Infection with Tb: When someone is infected with tuberculosis (TB) germs, the body develops a protective response against them. The TB skin test is a test of the body's response to tb, not the germs themselves. One can have an active infection where they are coughing out TB germs and are a risk to spread tb. Or the body may have had the infection long ago and controlled it so there is no risk now of spread. ...Read more

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When you take TB test and no bubble pops up is it negative?

A positive: Tb test is associated with elevation you can feel at the injection site -- not likely to be a discrete bubble. Redness doesn't count -- you have to feel something. ...Read more

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When you get a TB test and no bubble pops up does that mean its negative?

Yes: If there is no raised area which measures at least 5 mm in diameter the test should be considered negative. ...Read more

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How long would it take for TB test marks to go away? Mine came back neg but the mark went from unremarkable to large and red after 4 days now. Thx.

TB Test: There can be several reasons why a TB test takes longer to reactt. If you do have a large reaction as you describe you should go back to your doctors office to show it to them as theymay decide it is a delayed positive test ...Read more

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If I tested negative from a TB test and had been around someone who tested positive am I at risk of contracting tb?

TB risk: Yes, the PPD test is not 100%. You might want to get it repeated a month later to see if it is booster positive. Of course it is also possible that you didn't catch it. Many doctors are around people with TB a lot and never catch it. ...Read more

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Could I be prevented from going to work until I get my TB test results back?

Depends: If your doctor suspects that you have open pulmonary tuberculosis, you could be prevented from going to work. ...Read more

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TB test: neg >72 hrs but now large lump as time goes on? How long for mark to go away?

TB test: neg >72 hrs but now large lump as time goes on? How long for mark to go away?

Negative, give time: As long as there was no hardened lump at the infection site within that first 72 hours that was greater than 15mm (or less if you have risk factors), you are still considered negative. It can take some people up to a week or so for the redness and swelling to recede. Try ice several times a day to help with any swelling. ...Read more

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Hi, I recently had a TB test. It looks round and red but no bump. It was read as negative by nurse buy after 5 days, the redness is still there.

Hi, I recently had a TB test. It looks round and red but no bump. It was read as negative by nurse buy after 5 days, the redness is still there.

No bump = negative: A PPD TB skin test is where one needle injects a tiny amount of material under the skin. It is used to check for exposure to tb. The "bump" is measured, and any redness is not measured unless it is raised above the normal skin surface. A "bump" is positive if 5, 10, or 15mm, depending on the patient's circumstances. If positive or if worried, a blood test is done. Redness resolves in a week or so. ...Read more

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I got a tb test its itching and red. Size of a quarter maybe but it doesn't seem to be swollen. Pos? Neg?

I got a tb test its itching and red. Size of a quarter maybe but it doesn't seem to be swollen. Pos? Neg?

Allergy to ppd: Some people get a 'reaction' like that to a ppd-but it's not indicative of a positive TB test-instead it's an allergy to the material used for the test. A doctor or trained professional can look at it and determine if it's positive based on 'firmness' (we call it induration) under the skin where the ppd was placed. Itchy and red skin is something else. If it's bad, some hydrocortisone cream helps ...Read more

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Is it possible to be spotting and a negative test result and be pregnant?

Is it possible to be spotting and a negative test result and be pregnant?

Trust the test: Home pregnancy tests are very accurate. They are the same tests used in a doctors office. They can detect a pregnancy 7-10 days after conception. The best time to take one is when you miss your period. If you doubt the result you can repeat it in 1-2 days. If you were pregnant the hormone level would rise enough for detection. ...Read more

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Could I get spotting and have a negative test result and still be pregnant?

Could I get spotting and have a negative test result and still be pregnant?

No.: A reliable pregnancy test with negative result means that you are either within two weeks from conception, or that you are no longer pregnant. A previously positive test that is now negative after spotting is consistent with miscarriage. ...Read more

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Can there be any long term effects after finally getting a negative test result with c. Diff?

Can there be any long term effects after finally getting a negative test result with c. Diff?

Probably not: But there is a risk of recurrence, especially if antibiotic therapy is required for a different process. ...Read more

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What percent, is a negative Hiv test result. At 6 weeks? Do I most likely not have it then. And what are the odds of contracting it one time exposure

What percent, is a negative Hiv test result. At 6 weeks? Do I most likely not have it then. And what are the odds of contracting it one time exposure

HIV nucleic acid: Test. A negative antibody test at 6 weeks does not exclude HIV infection. A negative HIV nucleic acid test would. The odds of getting the infection depends on the type of exposure and the viral load in the fluid to which you were exposed. ...Read more

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Took a TB test last monday & the nurse said it was negative on wednesday but now I have a red spot should I worry?

Took a TB test last monday & the nurse said it was negative on wednesday but now I have a red spot should I worry?

Not reversible: It is common for people to have some allergy to the components of the test medicine. The reaction for positive test is specifically the bump felt and not the redness. It will go away. ...Read more

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I am a medical assistant and had my TB test come back positive but cxr negative. Is there any follow up I should do?

I am a medical assistant and had my TB test come back positive but cxr negative. Is there any follow up I should do?

Yes: For a person with a positive PPD skin test and a negative chest x-ray, if he had a BCG vaccine in the past, he can do a quantiferon TB blood test to see if he was exposed to real TB or just to the BCG shot. If he never had a bcg, he can talk with his doctor to decide if he should take inh prophylaxis against tb. If it is not sure if he truly truly was positive on the skin test, he can repeat it. ...Read more

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If I take Benadryl (diphenhydramine) a day after I got the TB test will it interfere with it? (make it positive/negative)

No effect: The reactivity of the tuberculin test relies on immune factors not allergic responses. Benedryl will have no effect on that process. ...Read more

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I have this cough for 10 months now, medical tests including TB test are all negative. Antibiotics didn't help either. Please what could be wrong?

I have this cough for 10 months now, medical tests including TB test are all negative. Antibiotics didn't help either. Please what could be wrong?

Persistent cough?: You have had a persistent cough for ten months. If you are living with other human beings who do not have a similar cough you can be pretty confident that you don't have a very contagious condition. Think about cough secondary to post nasal drip, asthma, reflux. You should go see a pulmonary disease doctor. He will help you find out what's going on. Good luck. ...Read more

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Is it possible to be pregnant after getting a negative test result? I have polysystric but normally have regular cycles but it just over 2 weeks late.

Is it possible to be pregnant after getting a negative test result? I have polysystric but normally have regular cycles but it just over 2 weeks late.

Time and technique: A negative result on a test done too soon, does not rule out pregnancy. If you did the test correctly at two weeks after expected period, and it was negative, you not likely to be pregnant. You may repeat the test in 3-4 days or see your doctor for a blood test. ...Read more

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Would a negative ANA rule out lymphoma? Does lymphoma cause a positive ANA test result?

Would a negative ANA rule out lymphoma? Does lymphoma cause a positive ANA test result?

It does not: At your age, if you have lymphoma it's probably Hodgkin's. ANA really has nothing to do with malignant lymphoma. If you're worried about big lymph nodest, trust me -- lymphoma nodes are obviously very abnormal. Best wishes, and I hope you'll always stay actively involved with your health. ...Read more

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Can you have Lyme disease and still have a negative test result on the western blot test?

Can you have Lyme disease and still have a negative test result on the western blot test?

Possible: Lab tests have false negatives and false positives. Each lab test result needs to be interpreted in the clinical context. A person may have infection with lyme disease and may not make appropriate antibody and have a negative test while the test is working properly. ...Read more

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Can Truvada for 21 (stopped at 4 weeks past possible hiv exposure) cause a negative hiv test result at 11 weeks past possible exposure?

Can Truvada for 21 (stopped at 4 weeks past possible hiv exposure) cause a negative hiv test result at 11 weeks past possible exposure?

Yes & No: The purpose of the Truvada as I understand your question was to prevent HIV after you had an exposure to it. Assuming this is the case, then a negative HIV result could be that the Truvada did it's job or that your exposure was minimal and you did not contract HIV - Either way at 11 weeks, it's pretty safe to say you are HIV- and unless you have had another exposure will remain that way. ...Read more

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If I don't see my period but got a negative pregancy test result what does it mean?

If I don't see my period but got a negative pregancy test result what does it mean?

Depends: If you did not have sex since your last period, you are not pregnant. If you had sex since your last period, you should repeat the pregnancy test in 4-5 days. Use first morning urine and follow the instructions for the test carefully.
If you do not wish to be pregnant, use contraception all the time, every time. You may consider implanted contraceptive, or IUD.
Practice safe sex. ...Read more

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I hv been taking primolut n and my period has not come and I had a negative blood test result....wen shld I expect my period?

I hv been taking primolut n and my period has not come and I had a negative blood test result....wen shld I expect my period?

Irregular periods: Irregular periods are one of the most common problems obgyns treat. If this is one time problem it usually resolves on its own. If this is a recurring problem you should be evaluated. Infections ; hormonal changes can cause spotting. If there is a concern for pregnancy then do a home pregnancy test. There are many options available to help regulate the menstrual cycle. Schedule a visit. ...Read more

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Blood draw from rt a/c and tb test below it. 5 days later red dots around antecubital area and pimple next to red but neg tb test. Normal? Coincidence

Blood draw from rt a/c and tb test below it. 5 days later red dots around antecubital area and pimple next to red but neg tb test. Normal? Coincidence

2 seperate: Most probable cause is you had some minor localized reaction to the blood draw (possible contact dermatitis if you had a bandaide on the area or tape, etc.) and the TB test below the site of the same arm, would not have anything to do with the injection site of the blood draw. Best wishes. ...Read more

Dr. Klaus d Lessnau
1,215 Doctors shared insights

Tuberculosis (Definition)

A potentially serious infectious bacterial disease that ...Read more