title: Diminished human immunodeficiency virus type 1 DNA yield from dried blood spots after storage in a humid incubator at 37 degrees C compared to -20 degrees C.
abstract: Collecting whole blood on filter paper simplifies the processing, transport, and storage of specimens used for the diagnosis of human immunodeficiency virus type 1 (HIV-1) and other tests. Specimens may be collected in tropical or rural areas with minimal facilities for handling specimens. To compare simulated tropical conditions with freezer storage, we examined the stability of HIV-1 DNA in dried blood spots (DBS) stored in humid heat and at -20 degrees C. DBS were created by spotting 50-microl aliquots of whole blood on 903 filter paper. DNA was extracted from DBS at baseline and after 2, 6, or 12 months of storage at -20 degrees C or at 37 degrees C with approximately 85% humidity. The DNA was tested undiluted or diluted using the Amplicor HIV-1 DNA PCR (Roche), version 1.5. Each reaction was scored positive, negative, or indeterminate based on optical density. Results were compared between storage conditions and over time. A total of 1,832 reactions from 916 DBS were analyzed, including 100 DBS at baseline, 418 stored at -20 degrees C, and 398 stored at 37 degrees C. A chi-square test showed fewer positive reactions for DBS stored at 37 degrees C (55%) than for those stored at -20 degrees C (78%) (P < 0.0001). Samples stored at -20 degrees C showed little change in the probability of detection of HIV-1 DNA over time; the odds ratio (OR) was 0.93 after storage for 1 year. Samples stored at 37 degrees C demonstrated a significant change in detection at 1 year (OR, 0.29). We conclude that exposure of DBS to 37 degrees C and high humidity impaired the recovery of HIV-1 DNA from DBS, whereas DNA recovery was preserved when DBS were stored frozen.
authors.affiliation: University of Washington, Seattle Children's Hospital Research Institute, Seattle, Washington 98109, USA.
authors.forename: Caroline
authors.initials: C
authors.lastname: Mitchell
authors.forename: Cheryl
authors.initials: C
authors.lastname: Jennings
authors.forename: Donald
authors.initials: D
authors.lastname: Brambilla
authors.forename: Grace
authors.initials: G
authors.lastname: Aldrovandi
authors.forename: Angela Martin
authors.initials: AM
authors.lastname: Amedee
authors.forename: Ingrid
authors.initials: I
authors.lastname: Beck
authors.forename: James W
authors.initials: JW
authors.lastname: Bremer
authors.forename: Robert
authors.initials: R
authors.lastname: Coombs
authors.forename: Don
authors.initials: D
authors.lastname: Decker
authors.forename: Susan
authors.initials: S
authors.lastname: Fiscus
authors.forename: Joseph
authors.initials: J
authors.lastname: Fitzgibbon
authors.forename: Katherine
authors.initials: K
authors.lastname: Luzuriaga
authors.forename: John
authors.initials: J
authors.lastname: Moye
authors.forename: Paul
authors.initials: P
authors.lastname: Palumbo
authors.forename: Patricia
authors.initials: P
authors.lastname: Reichelderfer
authors.forename: Mohan
authors.initials: M
authors.lastname: Somasundaran
authors.forename: Wendy
authors.initials: W
authors.lastname: Stevens
authors.forename: Lisa
authors.initials: L
authors.lastname: Frenkel
mesh_terms: D015925:Cryopreservation; D004279:DNA, Viral / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics*; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D013048:Specimen Handling
chemical_list: D004279:DNA, Viral