Detection of Viral Nucleic Acid in Specimens Spotted on Commercial Filter Papers: A Review and Meta-Analysis.

Filter paper-based sampling has been widely used for the collection, transport, and storage of biological samples. This review and meta-analysis aggregated the performance of commercial filter paper matrices for nucleic acid detection across human and veterinary viral pathogens. The review was conducted according to PRISMA guidelines using PubMed®, Web of Science®, and Scopus™ databases. Using eligible studies, nucleic acid detection rates were calculated as the number of PCR-positive filter paper samples divided by the total number of expected positive sampling units, based on direct testing or experimental design. Detection rates were analyzed using a multilevel meta-analysis of proportions with nested random effects to account for clustering within studies. A total of 145 studies representing 39 filter paper types were included. Cellulose-based matrices, particularly Whatman® and FTA™ products, predominated in the literature, although polyester and glass fiber substrates were also represented. Detection rates varied widely by filter paper type (46.1% to 97.0%) and virus target (63.7% to 92.8%). Experimental conditions, including storage temperature, drying time, and humidity, were inconsistently reported across studies, but the findings indicated that filter paper composition and experimental conditions influenced viral nucleic acid recovery and detection. Overall, this review showed that the recovery and detection of viral nucleic acid from filter paper is variable. The review also highlighted the need for experimental designs providing rigorous comparisons of filter paper performance over a range of conditions.