Blood Ammonia Stability Revisited

Jack R. Hester; William J. Korzun; Lara U. Mabry

doi:10.29074/ascls.28.3.173

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Jack R. Hester, MS
1. Health Diagnostic Laboratory, Inc., Richmond, VA
William J. Korzun, PhD, DABCC, MT(ASCP)⇑
1. Virginia Commonwealth University, School of Allied Health Professions, Department of Clinical Laboratory Sciences, Richmond, VA
Lara U. Mabry, M.S., MLS(ASCP)^CM
1. Virginia Commonwealth University, School of Allied Health Professions, Department of Clinical Laboratory Sciences, Richmond, VA

Address for Correspondence: William J. Korzun, PhD, DABCC, MT(ASCP), Department of Clinical Laboratory Sciences, Virginia Commonwealth University, 301 College Street, P.O. Box 980583, Richmond, VA 23298-0583, 804-828-9469, wjkorzun{at}vcu.edu

Abstract

The instability of ammonia in whole blood has challenged clinical laboratory scientists to develop specimen collection and handling methods that produce reliable results for plasma ammonia concentration. Thirty-eight outpatients' plasma ammonia concentrations were measured after heparinized whole blood specimens from each subject were held for 5, 15, and 30 minutes at room temperature and “on-ice”. The plasma ammonia concentration from whole blood maintained “on-ice” for 5 minutes was designated the “reference value”. Plasma ammonia concentrations from whole blood maintained “on-ice” for 15 or 30 minutes prior to processing were not significantly different from the reference values (15 min., p~0.196; 30 min., p~0.512). Plasma ammonia concentrations from whole blood maintained at room temperature for 5, 15 and 30 minutes prior to processing were also not significantly different from the reference values (p~0.961, 0.610, and 0.948, respectively). These results suggest that reliable plasma ammonia concentrations may be obtained from heparinized whole blood maintained at room temperature for up to 30 minutes.