Filter paper sampling of whole blood and urine for the determination of D/L arabinitol ratios by mass spectrometry

The methodology described permits the determination of the ratios of the D and L enantiomers of arabinitol in a small dorp of venous (arm) or finger-puncture blood or of urine placed as a spot on conventional filter paper. Replicate analyses using samples from healthy subjects and patients with confirmed disseminated candidiasis gave results that are statistically indistinguishable from those obtained from serum or urine using technique previously developed by the authors. Replicate analyses (n = 8) on days 1, 3, 7, and 14, and on samples after roundtrip long distance airmail transportation revealed that the filter paper spots have storage stability for at least two weeks at room temperature and that samples can be safely transported. Advantages include the initiation of pediatric applications using finger or heel punctures, frequent samplings from adults using drops of blood from samples taken for unrelated routine tests, and the design of inter-institutional studies to evaluate the clinical utility of using D/L arabinitol ratios for the diagnosis and monitoring of disseminated candidiasis.