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

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 scanner method (n = 50). Results: Between-run precision was 4.7-10.2% and between-run 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.

Automated summary

The aim of this study was to develop a nondestructive method to estimate hematocrit in dried blood spots. Standards and controls were created, and the DBS were scanned using a flatbed scanner. Gray values and pixel areas were analyzed with open-source software to estimate hematocrit and volume. The results were compared with hematological analyzer and showed high precision and accuracy.