A validated method for the determination of hematocrit in dried blood spots using image analysis: Supplementary data

Aim: To develop a nondestructive method for the estimation of hematocrit (HCT) in dried blood spots
(DBSs). Materials & methods: Standards and controls were created (HCT range: 0.20–0.50 l/l) and DBS
scanned using a flatbed scanner. Gray values and pixel areas were analyzed with open-source software to
estimate HCT and volume, respectively. HCT obtained in whole blood using hematological analyzer was
compared with DBS scannermethod (n = 50). Results: Between-run precision was 4.7–10.2% and betweenrun
accuracy was 89.6–102.1%. In the hematological instrument comparison, 96% of the patient sample
results were within ±15%. Conclusion: The nondestructive method can be used to exclude patient DBS
samples with extreme HCT levels from further analysis and avoid bias on measured concentration.