Safety of PPD Testing During Pregnancy

Evidence Supporting Safety

• The Centers for Disease Control and Prevention (CDC) guidelines state that the Purified Protein Derivative (PPD) test is safe to administer during pregnancy, with no documented episodes of fetal harm resulting from its use, based on thousands of pregnant women who have undergone PPD skin testing 1
• The CDC recommends that pregnancy should not exclude a female healthcare worker from being skin tested as part of a contact investigation or regular skin-testing program 1
• The CDC explicitly states that pregnancy is not a contraindication to tuberculin skin testing, with a strong evidence base supporting this recommendation 1, 2

Indications for PPD Testing During Pregnancy

• PPD testing is indicated for pregnant women who are at high risk for tuberculosis exposure, have symptoms suggestive of active tuberculosis, have known exposure to someone with active tuberculosis, or are HIV-positive or at increased risk for HIV infection, according to the CDC guidelines 3, 4, 5

Interpretation of PPD Results in Pregnancy

• For pregnant women with HIV infection, ≥5 mm of induration is considered a positive reaction, based on recommendations from the CDC 6, 5

Management After Positive PPD Test in Pregnancy

• If a pregnant woman has a positive PPD test, a chest radiograph with appropriate abdominal/pelvic lead apron shielding should be performed to exclude active TB, followed by chemoprophylaxis with isoniazid, according to the CDC guidelines 3
• Isoniazid should be accompanied by pyridoxine (vitamin B6) to reduce the risk of neurotoxicity, with a moderate evidence base supporting this recommendation 3

Important Considerations

• The Mantoux method with intradermally injected 5 TU PPD should be used for PPD testing, rather than multiple puncture TB skin tests, based on CDC recommendations 6
• Anergy testing is no longer routinely recommended, but if performed, mumps and candida are appropriate control antigens, according to the CDC guidelines 6

Common Pitfalls to Avoid

• The CDC recommends against delaying PPD testing in pregnant women who need it, as the test has been proven safe 1
• The American College of Physicians recommends against confusing PPD testing with BCG vaccination, which is contraindicated during pregnancy, especially in HIV-infected persons 4, 3
• The CDC advises against interpreting a negative PPD test as definitively excluding TB, especially in immunocompromised patients, as false negatives can occur, with a strong evidence base supporting this recommendation 6