Use of laboratory information system data for indirect estimation of reference interval for vitamin B12

Background: In common, clinical laboratories use reference intervals recommended by the manufacturers. Various factors affect laboratory tests such as age, sex, diet and genetics. So, it is recommended for each laboratory to determine its own reference ranges for each test used. We aimed to establish our reference interval for vitamin B12. Methods: The data archive of laboratory information system was searched for a 1-year period between January and December, 2013. Among 2526 subjects searched for vitamin B12, 2368 remained (1-70 years old, 512 male and 1856 female) when we excluded the outliers for estimation of reference range for vitamin B12 with nonparametric method according to National Committee for Clinical Laboratory Standards (NCCLS) C28-A3 guidelines. Serum levels of vitamin B12 were determined with electrochemi-luminescent technique. Results: New reference interval for vitamin B12 derived from our results was 101-702 pg/mL, and was not affected by gender. Conclusions: New reference interval was different from the one recommended by the manufacturer. We suggest that established reference interval reflects our population better than the values recommended by the manufacturer.