Influence of a light meal on routine haematological tests.
BACKGROUND
Patient-related variables, such as physical exercise, stress and fasting status are important sources of variability in laboratory testing. However, no clear indications about fasting requirements exist for routine haematological tests, nor has the influence of meals been assessed.


METHODS
We studied 17 healthy volunteers who consumed a light meal containing a standardized amount of carbohydrates, protein and lipids. Blood was taken for routine haematological tests before the meal and 1, 2 and 4 hours thereafter.


RESULTS
One hour after the meal, neutrophil count and mean corpuscular haemoglobin (MHC) increased significantly, whereas lymphocyte and monocyte counts, red blood cell distribution width, haematocrit, and mean corpuscular volume decreased significantly. A clinically significant variation was only observed for lymphocytes. Two hours after the meal, a significant increase was observed for neutrophils and MCH, whereas lymphocytes, eosinophils, haemoglobin and haematocrit decreased significantly. Clinically significant variations were recorded for lymphocytes, red blood cells (RBC), haemoglobin, haematocrit and MCH. Four hours after the meal MCH was significantly increased, while lymphocytes, eosinophils, RBC, haemoglobin and haematocrit were significantly decreased. Clinically significant variations were recorded for neutrophils, eosinophils, RBC, hematocrit and MCH.


CONCLUSIONS
The significant variation of several haematological parameters after a light meal demonstrates that the fasting time needs to be carefully considered in order to interpret the results of haematological tests correctly.
Lippi
Giuseppe
G
Sezione di Chimica Clinica, Dipartimento di Scienze Morfologico-Biomediche University of Verona, Ospedale Policlinico G.B. Rossi, Verona, Italy. giuseppe.lippi@univr.it
Lima-Oliveira
Gabriel
G
Salvagno
Gian Luca
GL
Montagnana
Martina
M
Gelati
Matteo
M
Picheth
Geraldo
G
Duarte
Alberto José
AJ
Franchini
Massimo
M
Guidi
Gian Cesare
GC
D000328:Adult; D003951:Diagnostic Errors; D004435:Eating / Q000502:physiology*; D005188:False Negative Reactions; D005189:False Positive Reactions; D005215:Fasting / Q000097:blood; D005260:Female; D006403:Hematologic Tests; D006801:Humans; D008297:Male; D019518:Postprandial Period; D012016:Reference Values; D015203:Reproducibility of Results; D013997:Time Factors
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