Automated imaging of circulating fluorocytes for the diagnosis of erythropoietic protoporphyria: a pilot study for population screening.
OBJECTIVE
To improve the traditional fresh blood film method to a high-throughput analysis of the presence of circulating fluorescent red cells (fluorocytes) in erythropoietic protoporphyria (EPP) using an automated imaging system.


METHODS
Based on the autofluorescence of protoporphyrin, we used an automatic image acquisition platform for examining fluorocytes in peripheral blood with minimal sample preparation. The image acquisition is easy-to-use under automated operations of excitation, focusing, detection and data analysis. Quality image and semi-quantitative fluorescence measurement of fluorocytes can be generated in a single step. For high-throughput analysis, the platform can image more than 200 96-well micro-plates, i.e. 19200 samples, in approximately 10 hours. Importantly, the reagent cost of analysis is negligible.


RESULTS
In this pilot study, three EPP patients were diagnosed and 4000 normal individuals were screened for EPP by this method. Our results showed that the method can distinguish the overt case and asymptomatic carriers. It gives reliable evidence for rapid EPP screening.


CONCLUSIONS
This automated imaging system provides multiple advantages that improve the traditional fresh blood film method as a more effective diagnostic tool and facilitates population screening for EPP. As fluorocytes are present in the umbilical cord blood of EPP patients, this high-throughput method can be potentially used for newborn screening of EPP.
Lau
Kin-Chong
KC
Department of Chemical Pathology, Prince of Wales Hospital, Hong Kong, China.
Lam
Ching-Wan
CW
D001331:Automation; D004912:Erythrocytes / Q000473:pathology; D005294:Ferrochelatase / Q000097:blood / Q000235:genetics*; D006723:Hong Kong; D006801:Humans; D008403:Mass Screening / Q000379:methods; D010865:Pilot Projects; D046351:Protoporphyria, Erythropoietic / Q000097:blood / Q000453:epidemiology / Q000473:pathology*; D011524:Protoporphyrins / Q000097:blood* / Q000235:genetics; D012016:Reference Values
D011524:Protoporphyrins; D005294:Ferrochelatase