Colinesterasas en sangre total medidas con técnica semicuantitativa y en eritrocitos o plasma medidas con técnicas cuantitativas: relaciones

Abstract

Introduction. An equivalence model which allows comparison of blood cholinesterase values, measured by Lovibond® (semiquantitative technique), and Michel, EQM®, Monotest® (erythrocyte and plasma cholinesterases) values measured by quantitative techniques is required. Objective. The performance of Lovibond® (Edson tintometric and Limperos & Ranta techniques) were compared with quantitative techniques. Materials and methods. The experimental design was descriptive, cross-sectional, and prospective. From a working population (18-59 years) in Valle de Aburrá and Near East of Antioquia. 827 representative samples were chosen for their lack of exposure to cholinesterase-inhibiting plaguicides and affiliated to the Social Security System. Results. (1) 827 workers were classified by Lovibond® in four categories: 821 values with 75% of cholinesterase activity or greater (categories 75, 87.5 and 100%) and 6 with cholinesterase activity smaller than 75%. (2) With each quantitative method, the mean values of erythrocyte and plasmatic cholinesterase corresponding to the four values obtained with Lovibond® were statistically different to each other. (3) The mean values of each quantitative technique increased when increased the tintometric method value. (4) Lovibond® classified the low enzymatic erythrocyte activity very poorly (61-73%), but the classification of the low enzymatic plasma activity was almost completely in error (94-96%). Conclusion. The values of erythrocyte or plasma cholinesterase were adequately estimated by both the quantitative techniques of Michel and EQM® and by Lovibond, but only when the enzymatic activity is normal. Lovibond®, however, had a poor capacity to designate as "low" the values that were low according to the quantitative tests.