Screening of folate status with use of dried blood spots on filter paper.
BACKGROUND
Dried blood spots (DBS) on filter paper have been a successful and economical matrix for neonatal screening.


OBJECTIVE
Our objective was to develop and evaluate an optimized method for DBS folate analysis and to assess DBS folate stability.


METHODS
DBS were eluted from paper by sonication in 5 g ascorbic acid/L containing 0.1% (by vol) Triton X-100 and hemoglobin folate values (HF; as pmol/g) were calculated from DBS eluate folate and hemoglobin concentrations.


RESULTS
Over 95% of DBS folate was eluted during a standardized sonication cycle and DBS folate assay reproducibility was acceptable both within (CV: <8%) and between (CV: <9%) runs. HF means (+/-1 SD) from finger-stick DBS and conventional venous methods were 2513 +/- 1144 and 2607 +/- 1195 pmol/g, respectively, in blood samples taken concurrently from 80 donors, and they correlated well (r = 0.97, P < 0.001). HF values and erythrocyte folate measures may be interconverted by using the mean cell hemoglobin concentration.


CONCLUSIONS
The DBS matrix has potential as an inexpensive and practical option for folate screening studies.
O'Broin
S D
SD
Department of Haematology, St James's Hospital, Dublin, Ireland. nutrition@stjames.ie
Gunter
E W
EW
D001801:Blood Stains; D004355:Drug Stability; D004912:Erythrocytes / Q000737:chemistry; D005374:Filtration / Q000295:instrumentation; D005492:Folic Acid / Q000097:blood*; D006801:Humans; D016014:Linear Models; D008403:Mass Screening / Q000379:methods*; D009752:Nutritional Status; D010209:Paper; D015203:Reproducibility of Results
D005492:Folic Acid