title: Comparison of three instruments for measuring red blood cell aggregation.
abstract: The International Society for Clinical Hemorheology organized a workshop to compare three instruments for measuring RBC aggregation: LORCA, Myrenne Aggregometer and RheoScan-A. The Myrenne Aggregometer provides indices at stasis (M) and at low shear (M1), with four indices obtained with the LORCA and RheoScan-A: amplitude (AMP), half-time (T1/2), surface area (SA) above (LORCA) or below (RheoScan-A) the syllectogram, and the ratio (AI) of the area above (LORCA) or below (RheoScan-A) the syllectogram to total area (AI). Intra-assay reproducibility and biological variability were determined; also studied were RBC in diluted plasma and in 1% 500 kDa dextran, and 0.003% glutaradehyde (GA)-treated cells in plasma. All measurements were performed at 37 degrees C. Standardized difference values were used as a measure of power to detect differences. Salient results were: (1) intra-assay variations below 5% except for RheoScan-A AMP and SA; (2) biological variability greatest for T1/2 with other indices similar for the three devices; (3) all instruments detected progressive changes with plasma dilution; (4) the Myrenne and LORCA, but not the RheoScan-A, detected differences for cells in dextran; (5) GA-treatment significantly affected the LORCA (AMP, T1/2, SA, AI), the RheoScan-A (AMP, SA, AI) and the Myrenne M parameter. It is concluded that: (a) the LORCA, Myrenne and the RheoScan-A have acceptable precision and suitable power for detecting reduced aggregation due to plasma dilution; (b) greatly enhanced RBC aggregation may not be sensed by the RheoScan-A while the Myrenne M1 index may be insensitive to minor increases of cell rigidity; (c) future studies should define each instrument's useful range for detecting RBC aggregation.
authors.affiliation: Department of Physiology, Faculty of Medicine, Akdeniz University, Antalya, Turkey. baskurt@akdeniz.edu.tr
authors.forename: Oguz K
authors.initials: OK
authors.lastname: Baskurt
authors.forename: Mehmet
authors.initials: M
authors.lastname: Uyuklu
authors.forename: Pinar
authors.initials: P
authors.lastname: Ulker
authors.forename: Melike
authors.initials: M
authors.lastname: Cengiz
authors.forename: Norbert
authors.initials: N
authors.lastname: Nemeth
authors.forename: Tamas
authors.initials: T
authors.lastname: Alexy
authors.forename: Sehyun
authors.initials: S
authors.lastname: Shin
authors.forename: Max R
authors.initials: MR
authors.lastname: Hardeman
authors.forename: Herbert J
authors.initials: HJ
authors.lastname: Meiselman
mesh_terms: D000328:Adult; D001799:Blood Sedimentation; D004903:Erythrocyte Aggregation / Q000502:physiology*; D004907:Erythrocyte Deformability / Q000502:physiology; D004912:Erythrocytes / Q000502:physiology*; D018056:Hemorheology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012212:Rheology / Q000295:instrumentation*