Fig 1.

The SAMBA Flu duplex test. Examples of influenza virus A-positive, influenza virus B-positive, and negative results. The signal strengths of the IC and influenza A/B test lines were graded from 0 to 5 according to an in-house scoring chart. A blank dipstick (no IC or influenza A/B signal) indicated an invalid test run and required repeat of the entire test procedure. The presence of the IC signal is not required for a valid influenza virus-positive call, i.e., the IC can be out-competed by a very high viral load sample in rare cases.