title: Quantitation of cytomegalovirus DNA load in dried blood spots correlates well with plasma viral load.
abstract: An assay to accurately quantitate cytomegalovirus (CMV) load in finger-stick-collected dried blood spots (DBS) could potentially be useful for field studies or for analyzing patient self-collected specimens. We therefore assessed CMV DNA load in paired venipuncture-collected plasma samples and finger-stick DBS, using a previously validated quantitative PCR assay. Assay variability, sensitivity, and changes in viral load during antiviral therapy in finger-stick DBS were compared to the reference plasma quantitative PCR assay, using 106 prospectively collected pairs of finger-stick DBS and plasma samples from 35 solid-organ transplant (SOT) patients. The DBS assay showed good agreement with the reference plasma viral load assay on the log10 scale (Pearson correlation coefficient, 0.92; P < 0.001). The 95% limit of detection of the DBS assay was estimated at 2,700 plasma copies/ml (675 plasma IU/ml). In 94% (76/81) of paired DBS and plasma samples above the limit of detection, the difference in CMV load was <1 log10. CMV viral load changes during antiviral treatment were comparable in plasma and DBS. We conclude that finger-stick DBS provides a convenient sample type for quantitation of CMV load that correlates well with plasma levels. Future studies to optimize and evaluate this methodology for patient self-collected samples are warranted.
authors.affiliation: Department of Medicine, University of Washington, Washington, USA. limaye@u.washington.edu
authors.forename: Ajit P
authors.initials: AP
authors.lastname: Limaye
authors.forename: Tracy K
authors.initials: TK
authors.lastname: Santo Hayes
authors.forename: Meei-Li
authors.initials: ML
authors.lastname: Huang
authors.forename: Amalia
authors.initials: A
authors.lastname: Magaret
authors.forename: Michael
authors.initials: M
authors.lastname: Boeckh
authors.forename: Keith R
authors.initials: KR
authors.lastname: Jerome
mesh_terms: D000328:Adult; D000368:Aged; D001769:Blood / Q000821:virology*; D003587:Cytomegalovirus / Q000302:isolation & purification*; D003586:Cytomegalovirus Infections / Q000821:virology; D004279:DNA, Viral / Q000302:isolation & purification; D003890:Desiccation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010949:Plasma / Q000821:virology*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods*; D014180:Transplantation; D019562:Viral Load / Q000379:methods*
chemical_list: D004279:DNA, Viral