Table 3.

Comparison of assay performance across specimen types and kitsa

Comparison% Detectability number of markersbMedian concentration number of markersc
Bio-Rad (45 markers)
T0 serum vs. T0 heparin plasma
 Significantly higher in serum716
 Significantly higher in plasma1019
 Similar2110
 Not evaluabled7
T3 EDTA plasma vs. T3 heparin plasma
 Significantly higher in EDTA27
 Significantly higher in heparin212
 Similar3226
 Not evaluable9
Millipore (71 markers)
 T0 serum vs. T0 heparin plasma
 Significantly higher in serum418
 Significantly higher in plasma513
 Similar5140
 Not evaluable11
T3 EDTA plasma vs. T3 heparin plasma
 Significantly higher in EDTA53
 Significantly higher in heparin130
 Similar4938
 Not evaluable16
Bio-Rad vs. Millipore (23 markers)
 T0 Serum
 Significantly higher in Bio-Rad215
 Significantly higher in Millipore27
 Similar101
 Not Evaluable9
T0 heparin plasma
 Significantly higher in Bio-Rad416
 Significantly higher in Millipore47
 Similar60
 Not evaluable9
T3 EDTA plasma
 Significantly higher in Bio-Rad315
 Significantly higher in Millipore38
 Similar70
 Not evaluable10
  • aComparisons were restricted to markers with acceptable performance—45 Bio-Rad markers, 71 Millipore markers, and 23 markers measured using both kits.

  • bComparisons of percentage of detectability across specimen types and kits were conducted using the McNemar's test.

  • cComparisons of median observed concentrations across specimen types and kits were conducted using the Wilcoxon signed-rank test. Observations below the assay's lower limit were excluded.

  • dMcNemar's P value could not be evaluated because one of the groups had 100% detectability.