New Molecular Testing
Nucleic acid amplification testing (NAAT) methods directly applicable to stool specimens have recently become available, and these tests offer improved accuracy and turn-around-time compared to older methods. The new NAAT to be offered at LifeLabs has published sensitivity and specificity of 92-95% and 99%, respectively. Studies of the new NAAT method at LifeLabs demonstrated greater than 95% accuracy overall compared to the gold standard toxigenic culture by PCR. Results of testing with the new method will generally be available within 48 hours and often within 24 hours of specimen receipt.
Effective June 3, 2013, LifeLabs will change to a direct nucleic acid amplification test for detection of toxigenic C. difficile in stool specimens. This test will replace direct toxin detection in stool specimens by enzyme immunoassay (EIA) backed up by toxigenic culture for C. difficile by PCR for EIA negative specimens. The new test offers improved diagnostic accuracy compared to EIA testing and more rapid result reporting than toxigenic culture.