Anticoagulant Proteins in a Population of Mexican Mestizo Donors Luis Antonio Meill on-Garcı´a, 1 Edgar Hern andez-Zamora, 2 Guadalupe Montiel-Manzano, 1 Cesar Zavala-Hern andez, 3 Eduardo Ramı´rez-San Juan, 4 Gabriela Cesarman-Maus, 5 and Elba Reyes-Maldonado, 6 Mexico City, Mexico Background: To determine the activity of antithrombin (AT), protein C (PC), and protein S (PS), as well as the frequency of deficiencies of these proteins in a population of healthy Mexican mestizo blood donors. Methods: AT, PC, and PS were determined from 1,502 plasma samples of healthy blood do- nors by using commercial kits in a coagulometer 4 STA (Diagnostica Stago, Asni  eres, France). Results: A total of 741 women and 761 men were under study. They were divided into age range groups (18e24, 25e34, 35e44, 45e54, and 55e64 years). Activity of AT, PC, and PS was determined. For AT, activity values were specific for each age group according to gender when it had to do with PS, as well as when PC was determined. Frequencies of AT, PC, PS, and activated PC resistance activity deficiencies were obtained from reference levels (RLs) and average levels of this study. Differences were found between both frequencies for AT, PC, and PS, and the average levels obtained were used in this study. The frequencies of the activity deficiencies obtained through the values gotten in this population were: AT, 0.6%; PC, 1.06% (which is higher than the one obtained using the RLs described by commercial kits 0.33% and 0.66%, respectively); and PS, 1% (which is less than 4.5%). Conclusions: It is necessary to know the characteristics and biological behavior of the coagu- lation proteins in the Mexican population because the RLs used have been established for pop- ulations that are genetically different. INTRODUCTION Hypercoagulable states are disorders related to he- mostatic imbalance and predispose individuals to develop thromboembolic events. 1 In hereditary thrombophilia, the most common disorders are deficiencies of antithrombin (AT), protein C (PC), and protein S (PS), as well as mutations of prothrombin gene (PT20210), which leads to elevated factor II plasma levels, dysfibrinogene- mia, and activated protein C resistance (APCR) L. A. M.-G. and E. H.-Z. contributed equally to the preparation of this article. Funding: This work was supported in part by the Gonzalo Rı´o Arronte IAP Foundation, the Roche Diagnostic Company Mexico, and the Instituto Polit  ecnico Nacional. 1 Hematology Department, Centro M edico Nacional Siglo XXI, Mexico City, Mexico. 2 Genetic Department, Instituto Nacional de Rehabilitaci on, Mexico City, Mexico. 3 Pathology Central Laboratory, Instituto Nacional de Rehabilitaci  on, Mexico City, Mexico. 4 Physiology Department, Escuela Nacional de Ciencias Biol ogicas, Instituto Polit  ecnico Nacional, Mexico City, Mexico. 5 Hematology Department, Instituto Nacional de Cancerologı´a, Mexico City, Mexico. 6 Morphology Department, Cytology Laboratory, Escuela Nacional de Ciencias Biol ogicas, Instituto Polit  ecnico Nacional, Mexico City, Mexico. Correspondence to: Elba Reyes-Maldonado, PhD, or Edgar Hern andez- Zamora PhD. Prol. Carpio y Plan de Ayala s/n, Col. Santo Tom as, Delegaci on Miguel Hidalgo, C.P. 11340, Escuela Nacional de Ciencias Bio- l ogicas, Instituto Polit  ecnico Nacional, Mexico City, Mexico; E-mails: elbareyesm@gmail.com or edgarhz1969@yahoo.com.mx Ann Vasc Surg 2015; 29: 222–226 http://dx.doi.org/10.1016/j.avsg.2014.09.023 Ó 2015 Elsevier Inc. All rights reserved. Manuscript received: May 20, 2014; manuscript accepted: September 4, 2014; published online: November 24, 2014. 222