Original Article

Ann Lab Med 2012; 32(4): 250-256

Published online July 1, 2012

Copyright © Korean Society for Laboratory Medicine.

Influence of a Regular, Standardized Meal on Clinical Chemistry Analytes

Gabriel Lima-Oliveira, M.S.1,2,3,4,*, Gian Luca Salvagno, M.D.1,*, Giuseppe Lippi, Ph.D.5, Matteo Gelati, M.T.1,
Martina Montagnana, M.D.1, Elisa Danese, M.D.1, Geraldo Picheth, Ph.D.2, and Gian Cesare Guidi, Ph.D.1,2

Laboratory of Clinical Biochemistry1, Department of Life and Reproduction Sciences, University of Verona, Italy; Post-Graduate Program of Pharmaceutical
Sciences2, Department of Medical Pathology Federal University of Parana, Brazil; MERCOSUL3, Sector Committee of Clinical Analyses and In Vitro Diagnostics-
CSM 20, Brazil; Brazilian Society of Clinical Analyses on Sao Paulo State4, Brazil; Laboratory of Clinical Chemistry and Hematology, Department of Pathology
and Laboratory Medicine5, Academic Hospital of Parma, Italy

Correspondence to: Gabriel Lima-Oliveira
Av. Pref. Lothário Meissner 632, Jardim Botânico, Curitiba-PR, 80210-170, Brazil
Tel: +55-41-33604067
Fax: +55-41-33604067
*These authors contributed equally to this work.

Received: January 26, 2012; Revised: March 27, 2012; Accepted: May 25, 2012

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background: Preanalytical variability, including biological variability and patient preparation, is an important source of variability in laboratory testing. In this study, we assessed whether a regular light meal might bias the results of routine clinical chemistry testing. Methods: We studied 17 healthy volunteers who consumed light meals containing a standardized amount of carbohydrates, proteins, and lipids. We collected blood for routine clinical chemistry tests before the meal and 1, 2, and 4 hr thereafter. Results: One hour after the meal, triglycerides (TG), albumin (ALB), uric acid (UA), alkaline phosphatase (ALP), Ca, Fe, and Na levels significantly increased, whereas blood urea nitrogen (BUN) and P levels decreased. TG, ALB, Ca, Na, P, and total protein (TP) levels varied significantly. Two hours after the meal, TG, ALB, Ca, Fe, and Na levels remained significantly high, whereas BUN, P, UA, and total bilirubin (BT) levels decreased. Clinically significant variations were recorded for TG, ALB, ALT, Ca, Fe, Na, P, BT, and direct bilirubin (BD) levels. Four hours after the meal, TG, ALB, Ca, Fe, Na, lactate dehydrogenase (LDH), P, Mg, and K levels significantly increased, whereas UA and BT levels decreased. Clinically significant variations were observed for TG, ALB, ALT, Ca, Na, Mg, K, C-reactive protein (CRP), AST, UA, and BT levels. Conclusions: A significant variation in the clinical chemistry parameters after a regular meal shows that fasting time needs to be carefully considered when performing tests to prevent spurious results and reduce laboratory errors, especially in an emergency setting.

Keywords: Blood specimen collection, Clinical laboratory techniques, Diagnostic errors,
Eating, Fasting, Postprandial period, Reference values, Reproducibility of results, Quality
control, Specimen handling