Background: Zinc protoporphyrin (ZPP) testing has been studied previously as a substitute for ferritin (fer) testing of blood donors in determining iron stores.
Objective: To determine whether ZPP testing could be performed using specimens collected via the capillary (cap) finger-stick (FS) method, similar to predonation hemoglobin (HB) testing. Also, we evaluated the correlation among FS HB, venous (ven) ZZP, FS ZPP, and ven fer levels as predictors of iron depletion.
Methods: Blood donations from 328 study participants were evaluated using FS HB assay; we also performed ven ZPP, cap ZPP, and ven fer testing. We assessed the donors for subclinical iron deficiency (fer levels <26 ng/mL and ZPP levels >100 μmol/mol heme).
Results: Subclinical iron deficiency was present among first-time and repeat blood donors at all HB levels. Variation among test results (FS HB, ven fer, ven ZPP, and FS ZPP) was statistically significant (P <.001).
Conclusion: Insufficient correlation existed regarding FS HB and ven fer test results to support use of ZPP to determine iron stores in blood donors.