What does it mean when a TB test is indeterminate?

What does it mean when a TB test is indeterminate?

An indeterminate result indicates an uncertain likelihood of M. tuberculosis infection. A borderline test result (T-Spot only) also indicates an uncertain likelihood of M. tuberculosis infection.

What do you do if Quantiferon gold is indeterminate?

An indeterminate QFT-G result does not provide useful information regarding the likelihood of M. tuberculosis infection. The optimal follow-up of persons with indeterminate QFT-G results has not been determined. The options are to repeat QFT-G with a newly obtained blood specimen, administer a TST, or do neither.

When should a TB test be read back?

The skin test reaction should be read between 48 and 72 hours after administration by a health care worker trained to read TST results. A patient who does not return within 72 hours will need to be rescheduled for another skin test. The reaction should be measured in millimeters of the induration (firm swelling).

When can a TB patient be removed from isolation?

Home isolation may be discontinued when the patient is deemed non-infectious and meets all the following criteria: Patient must be receiving and tolerating appropriate four-drug TB treatment for fourteen days or more via DOT; Patient must show clinical improvement or be asymptomatic; and.

Why might a patient test indeterminate?

An indeterminate result means that the test kit shows a weak positive reaction, perhaps because of an unknown antibody cross-reaction, because of cross-contamination with another person’s sample or because of another technical error.

What does indeterminate mean in medical terms?

An indeterminate diagnostic test result can be defined as a result that adds no additional diagnostic information to the original (pre-test) likelihood of having the condition, so that the test result does not alter the likelihood of having the condition.

When do you repeat indeterminate Quantiferon?

The QFT-2G test and the tuberculin skin test (TST) were performed for all subjects. If the results of the QFT-2G test were indeterminate, the test was repeated within 1 month.

Does Quantiferon become negative after treatment?

After three months 87.5% were still QFT-TB positive (35/40 tested) whereas after 15 months, one year after the end of therapy, 84.6% remained positive (22/26 tested). All patients with reversed QFT-TB test after three months were still negative at 15 months.

How long is at spot test good for?

Minimum state regulations require TB screening once every 4 years. School staff members may request TB testing more frequently from their health care provider, but school districts are not required to provide it more than once every 4 years.

How do you know if your TB test is negative?

What if my TB skin test is negative? The test is “negative” if there is no bump (or only a very small bump) at the spot where the fluid was injected. A negative TB skin test usually means that you don’t have TB. In some situations, you may need to have another TB skin test later.

When is a TB patient non infectious?

Patients can be considered noninfectious when they meet all of the following three criteria: They have three consecutive negative AFB sputum smears collected in 8- to 24-hour intervals (one should be an early morning specimen); They are compliant with an adequate treatment regimen for two weeks or longer; and.

Do people with TB have to quarantine?

Descriptive Note: Quarantine is a disease control measure that applies to individuals who have been exposed to a communicable disease but are not yet ill. Individuals who are latently infected with TB pose no risk of transmission; therefore, quarantine is not an appropriate disease control measure for TB.

When to repeat an Igra test for tuberculosis (TB)?

In addition, repeating an IGRA or performing a TST might be useful when the initial IGRA result is indeterminate, borderline, or invalid and a reason for testing persists. Multiple negative results from any combination of these tests cannot exclude M. tuberculosis infection.

What does a negative TB tube test result mean?

You can now see why a negative result in the TB tube doesn’t mean much (ie, the result is “indeterminate”) when the T-cells don’t respond to non-specific antigens. This situation is analogous to calling a PPD “negative” when a patient is anergic!

How long does it take for tuberculin reaction to show up?

The skin test reaction should be read between 48 and 72 hours after administration. A patient who does not return within 72 hours will need to be rescheduled for another skin test. If a person does not return within 48-72 hours for a tuberculin skin test reading, a second test can be placed as soon as possible.

How is tuberculosis (TB) disease excluded from a diagnosis of LTBI?

A diagnosis of LTBI requires that TB disease be excluded by medical evaluation. This should include checking for signs and symptoms suggestive of TB disease, a chest radiograph, and, when indicated, examination of sputum or other clinical samples for the presence of M. tuberculosis.