A poster presented at ID Week 2016 showed that novel DIAs have higher sensitivity for influenza A and B compared to traditional RIDTs
, with equal specificity when compared to a high-sensitivity reference test.
are point-of-care tests that provide results within 30 minutes; however, with reported sensitivities of 10%-80%, negative test results can be unreliable (6-9).
Among the 150 RT-PCR positive cases, there were 53 RIDT
positive (true positive rate or sensitivity = 35.
When the RIDT
was run on these samples, there were 49 negative results and 31 positive results.
Physician-ordered diagnostic tests, including RIDT
(eight patients), rapid test for respiratory syncytial virus (RSV) (one), Legionella urinary antigen (three), Streptococcus pneumoniae urinary antigen (one), and bacterial cultures on bronchoalveolar lavage (BAL) (one), sputum (one), and blood specimens (five) collected 0-7 days after illness onset all were negative; however, among two of the five patients with blood specimens, blood was collected for bacterial culture 4 days after antibiotic therapy was initiated.
Overall, no commercial brand of RIDT
seemed to perform markedly better or worse than the others, but this finding should be interpreted cautiously because head-to-head comparisons were not done in most studies.
The CDC notes that RIDTs
have suboptimal test sensitivity, and false-negative results are common when flu activity is high.
Each influenza virus had variable levels of positivity with RIDTs
, suggesting that several viruses of each type and subtype should be evaluated with each RIDT
on a regular basis.
To determine the diagnostic accuracy of RIDT
for H1N1 influenza, Dr.
Traditionally, rapid influenza virus antigen diagnostic tests, first introduced in the 1990s and commonly known as RIDTs
, have been used in these types of situations to help detect influenza infections.
Positive and negative controls contained in each RIDT
were run before testing the viruses in the study to verify performance of each assay lot, with the exception of FluAlert, which does not provide controls.
Influenza testing, in particular, is frequently targeted for standardization in large health systems due to the ready availability of CLIA-waived RIDT