Citrulline levels in a paediatric age group: does measurement on dried blood spots have additional value?
BACKGROUND
Citrulline is considered to be a marker of absorptive enterocyte mass. Citrulline levels can be measured in plasma or dried blood spot (DBS) samples. The purpose of this study is to calculate reference intervals for plasma and DBS citrulline concentrations in children and to examine the effect of age and gender.


METHODS
In 151 healthy subjects ranging from 1 month to 20 years of age, plasma and DBS citrulline concentration were determined by using Liquid Chromatography-tandem Mass Spectrometry. Citrulline concentrations were examined in relation to age and gender. Reference values were calculated according to the guidelines of the International Federation of Clinical Chemistry and the National Committee on Clinical Laboratory Standards.


RESULTS
No significant influence of age and gender could be discerned on plasma or DBS citrulline concentration. In children, the reference intervals for citrulline bounded by the 2.5 and 97.5 percentiles are 13.31-69.05 μmol/L and 23.70-49.04 μmol/L for plasma and DBS samples respectively.


CONCLUSIONS
The reference intervals for citrulline levels in healthy children are widely dispersed. Measuring citrulline concentrations in dried blood spots delivers no additional value to plasma measurements for the calculation of reference intervals in children.
Department of Neonatology, Ghent University Hospital, Ghent, Belgium.
Linde
L
Goossens
Mieke
M
Bouvry
Piet
P
Vanhaesebrouck
Birgitte
B
Wuyts
Georges
G
Van Maele
Eddy
E
Robberecht
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002853:Chromatography, Liquid; D002956:Citrulline / Q000097:blood*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D013048:Specimen Handling; D053719:Tandem Mass Spectrometry; D055815:Young Adult
D002956:Citrulline