Microscopic or occult hematuria, when reflex testing is not good laboratory practice.
Consensus opinion suggests that hematuria found by dipstick and not confirmed on microscopic examination (<2 erythrocytes per high power field) signifies a false-positive reagent strip test result. Standard practice is to repeat the dipstick test several days later and if still positive to confirm by microscopic examination. If discordant results are obtained, experts recommend reflex testing for urinary myoglobin and hemoglobin concentrations. The question is whether or not this approach represents good laboratory practice. These recommendations are not evidence based. We conclude that the reference range for red blood cells on the reagent strip should be increased to 25x10(6) cells/L for young men, and 50x10(6) cells/L for the rest of the adult population, ranges consistent with flow cytometry reports. Confirmation reflex testing using tests that have inferior sensitivity, precision and probably accuracy is not recommended.
Central Laboratories Haifa and Western Galilee, Clalit Health Services, Nesher - Israel. paulfr@clalit.org.il
Paul
P
Froom
Mira
M
Barak
D006417:Hematuria / Q000175:diagnosis*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D008853:Microscopy; D009211:Myoglobin / Q000032:analysis; D011934:Reagent Strips; D012016:Reference Values
D006454:Hemoglobins; D009211:Myoglobin; D011934:Reagent Strips