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INTER-LABORATORY STUDY OF CELLULAR FLUORESCENCE INTENSITY MEASUREMENTS WITH FLUORESCEIN-LABELED MICROBEAD STANDARDS
Citation:
Vogt, R., G. Cross, D. Phillips, L. Henderson, AND W. Hannon. INTER-LABORATORY STUDY OF CELLULAR FLUORESCENCE INTENSITY MEASUREMENTS WITH FLUORESCEIN-LABELED MICROBEAD STANDARDS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/096 (NTIS PB92153899).
Description:
To determine the precision of cellular fluorescence intensity (FI) measurements derived from labeled microbead standards, FI results were compared from 43 different flow cytometers in 34 laboratories. ll laboratories analyzed prepared aliquots of fluoresceinated calf thymocyte nuclei (Fluorotrol), human lymphocytes stained with fluoresceinated anti-CD4 antibody, and fluoresceinated microbeads used as both internal and external standards. easurements were conducted by most laboratories on the third and fourth days after sample preparation. esults for percent of events within the gates and the histograms returned by participants indicated that the samples had remained stable and that grated populations had been properly identified. ll standard curves shoved strong linearity, and the pooled results from all standards produced a best-fit curve that was in close agreement with the assigned values. onetheless, results for cellular FI were highly variable, with CVs of 2O-34%. greement within lab/instrument was much better, with CVs ranging from 3.0 to 9.9%. he overall variability was not obviously attributable to differences in the types of cytometer, not could it be explained by attributes of the standard curves or any other single variable examined. owever, the application of a corrective factor based on FI results for Fluorotrol allowed a two-fold improvement in the precision of FI measurements on CD4-stained lymphocytes, with an overall CV of 11%. ncharacterized differences In the operating conditions of flow cytometers can influence cellular FI measurements, but consistent results can be obtained if a stained cellular calibrator is analyzed in addition to the proper microbead standards.
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INTER-LABORATORY STUDY OF CELLULAR FLUORESCENCE INTENSITY MEASUREMENTS WITH FLUORESCEIN-LABELED MICROBEAD STANDARDS