Interpatient distributions of bloodspot area per fixed volume of application: Comparison between filter paper and non-cellulose dried matrix spotting cards

• Published in: Clinica chimica acta 2014-11, Vol.437, p.187-190
• Main Authors: McCloskey, Laura J., Yoo, Janet H., Stickle, Douglas F.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Blood Specimen Collection - instrumentation; Blood Specimen Collection - methods; Blood Specimen Collection - standards; Bloodspots; Dried Blood Spot Testing - instrumentation; Dried Blood Spot Testing - methods; Dried Blood Spot Testing - standards; Dried matrix spotting cards; Female; Filter paper; Filtration - standards; Hematocrit; Hematocrit - instrumentation; Hematocrit - methods; Hematocrit - standards; Humans; Male; Middle Aged; Paper - standards; Young Adult
• ISSN: 0009-8981; 1873-3492
• DOI: 10.1016/j.cca.2014.07.026

Non-cellulose dried matrix spotting (DMS) cards are an alternative to filter paper (FP) for bloodspots. We compared the interpatient distributions of bloodspot areas between DMS and FP for a fixed volume of application of whole blood, and examined correlations of areas with hematocrit. EDTA-whole blood adult patient samples (n=49; 25 males, 24 females) were utilized after routine measurement of hemoglobin and hematocrit. Replicate (4×) bloodspots were produced by bolus drop application of 50μL whole blood via a fixed-volume pipettor to either FP or DMS. Dried bloodspot areas were determined by image analysis. Hematocrits (HCT) were normally distributed (HCT=30.9±5.3%). For both FP and DMS, bloodspot areas (a, cm2) across patients were normally distributed: for FP, a=1.11±0.056cm2 (±5.0%); for DMS, a=0.378±0.037cm2 (±9.9%). Relative bloodspot area differences across the population range were >20% for both DMS and FP. Correlation of bloodspot areas to hematocrit was negative for FP (r=−0.80) but positive for DMS (r=+0.78). Interpatient variation in blood volume per area is a preanalytical variable for both DMS and FP bloodspots. Hematocrit is but one interpatient variable, as correlations of fixed-volume bloodspot areas with hematocrit across patients were substantially inexact (r2