Bivariate analysis for the sensitivity of Aspergillus PCR testing spiked plasma specimens distributed to 8 EAPCRI core centersa

VariableZ scorebP value
No. of plasma samples analyzed/mo−1.610.107
Plasma starting vol−2.500.01c
DNA elution vol−0.650.513
Ratio starting plasma vol to elution vol−2.320.02c
Total PCR vol−2.640.01c
Template vol−1.470.141
Use of internal control−4.900.00c
Use of ≥2 replicates−2.310.02c
% of eluate vol used in PCR−0.950.343
  • a All continuous and binary center-specific covariates were included into the basic model.

  • b With a negative Z score, the variable tended to exert a favorable effect on the PCR assay.

  • c Covariates exerting a significant effect (P < 0.05) and an absolute Z score of >1.96.