VALIDATION OF DESCRIPTIVE PARAMETERS OF RBC AGGREGATION OBTAINED WITH A CHIP AGGREGOMETER BASED ON LASER TRANSMISSION

MARTÍN TODERI; BIBIANA RIQUELME; ANALÍA I. ALET; HORACIO V. CASTELLINI

Milan

Simposio; XXIX International Symposium on Technical Innovations in Laboratory Hematology; 2016

International Society for Laboratory Hematology (ISLH) y Societa Italiana di Patologia Clinica e Medicine di Laboratorio (SIPMeL)

Introduction: Phenomena associated with RBC aggregation have been of interest for many years. Most studies involve several scientific areas such as blood rheology, clinical medicine and in vivo observations. It is of great importance to develop techniques and equipment, that allow evaluation and characterization of the erythrocyte aggregation phenomenon. Human RBC tend to form aggregates which initially consist of face-to-face linear structures that resemble a stack of coins which are generally called rouleaux. Methods: RBC aggregation can be analyzed by recording the intensity of transmitted light through a blood sample in real time. The graphic of transmitted light intensity as a function of time is called syllectogram. Several normalized syllectograms of in vitro altered blood samples from healthy donors were obtained with a previously developed low cost disposable-chip aggregometer. Studies were carried out varying the erythrocyte surface electric charge by the digestion of trypsin, and altering the erythrocyte membrane using different anesthetics (propofol, remifentanil, vecuronium) in order to obtain representative curves of these situations. Dilution on physiological saline with albumin was used to assess the dependence of the syllectogram regarding ligands presence in suspension medium. A theoretical approach of RBC aggregation was considered to be able to obtain a characterization of the phenomenon by computational fitting of experimental data, the corresponding indexes were A (aggregation index) and D (desegregation index).Results: A minimum sample volume of 15µL was used and the parameters, Amp100: the normalized light intensity at 100 s, Amp750: the normalized light intensity at 750 s, t12: the time required to reach the 50% of the total amplitude of transmitted light, AI: the normalized area of the syllectogram, and M-Index: the integral of the syllectogram curve, were defined to assess computationally the data collected. Amp100 and t12 were the most sensible parameters regarding a reduced erythrocyte surface electric charge, and AI and M-Index were the most representatives of a variation in the plasmatic protein content of the suspension medium. SampleAmp100Amp750t1/2(A)Control12.1±1.185.0±4.1284±310.0022±0,0006Trypsin (2.5 mg/ml)19.0±1.886.6±2.4226±180.0026±0.0006Plasma 50% / SFA13.2±1.480.9±4.5334±180.0021±0.0006Conclusions: Typical values of the parameters were obtained for the situations studied characterizing the kinetics of erythrocyte aggregation. These alterations of human blood could be present in vascular pathologies and in the implementation of anesthetics, therefore, these kind of assessments are of interest for further applications in Anesthesiology and Clinical Medicine in general.