title: Accuracy of fluorocrit in determination of blood perflubron concentration.
abstract: Previous studies examining the radiosensitizing effects of perfluorochemical emulsions have based dose recommendations on a measurement known as fluorocrit. The fluorocrit is the proportion of blood volume occupied by perfluorochemicals and is measured using standard hematocrit procedures. This measurement is inherently crude and subject to error and variability between different individuals measuring the same sample. Furthermore, the fluorocrit method has not been compared to other quantitative methods to determine its reliability. The purpose of this study was to compare fluorocrit measurements to those obtained by gas chromatographic analysis. A 90% w/v perflubron emulsion was administered to six normal dogs once weekly for four weeks and peripheral blood samples were obtained at specified time points for analysis. A total of 123 blood samples were analyzed by both methods. The relationship between blood fluorocrit and plasma perflubron concentration measured by gas chromatography was examined using regression models. Based on the modest predictive value (r2 = 0.3683) of the derived statistical model, we conclude that fluorocrit measurement is an inaccurate method of estimation of blood perflubron concentration. Caution must, therefore, be exercised when extrapolating data and dose recommendations from reports of studies using flurocrit as the only estimate of blood perflubron concentration.
authors.affiliation: Department of Veterinary Medicine and Surgery, University of Missouri-Columbia 65211, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Henry
authors.forename: J W
authors.initials: JW
authors.lastname: Tyler
authors.forename: T
authors.initials: T
authors.lastname: Fields
authors.forename: W G
authors.initials: WG
authors.lastname: Brewer
authors.forename: N
authors.initials: N
authors.lastname: Royer
mesh_terms: D000818:Animals; D004285:Dogs; D004655:Emulsions; D005466:Fluorocarbons / Q000097:blood*; D006400:Hematocrit / Q000379:methods*; D006842:Hydrocarbons, Brominated; D011237:Predictive Value of Tests; D015203:Reproducibility of Results
chemical_list: D004655:Emulsions; D005466:Fluorocarbons; D006842:Hydrocarbons, Brominated; C003072:perflubron