Reverse Transcription-Polymerase Chain Reaction Testing on Filter Paper-Dried Serum for Laboratory-Based Dengue Surveillance-American Samoa, 2018.

Laboratory-based surveillance for arboviral diseases is challenging in resource-limited settings. We evaluated the use of filter paper-dried sera for detection of dengue virus (DENV) RNA during an outbreak in American Samoa. Matched liquid and filter paper-dried sera were collected from patients with suspected dengue and shipped to a reference laboratory for diagnostic testing. RNA was extracted from each sample and tested for DENV RNA by real-time reverse transcription-polymerase chain reaction (RT-PCR). Of 18 RT-PCR-positive liquid specimens, 14 matched filter paper-dried specimens were positive for a sensitivity of 78% (95% CI, 55-91%). Of 82 RT-PCR-negative liquid specimens, all filter paper-dried specimens were negative for a specificity of 100% (95% CI, 96-100%). Shipping of filter paper-dried specimens was similarly timely but less expensive than shipping liquid sera. Using filter paper-dried serum or blood can be a cost-effective and sustainable approach to surveillance of dengue and other arboviral diseases in resource-limited settings.