Annals of Clinical Biochemistry > Volume 45, Number 1 > Pp. 83-87

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ford, L. Articles by Berg, J. Search for Related Content PubMed PubMed Citation Social Bookmarking                      What's this?

Original Article

Delay in separating blood samples affects creatinine measurement using the Roche kinetic Jaffe method

Loretta Ford  and Jonathan Berg

Clinical Biochemistry Department, City Hospital, Dudley Road, Birmingham B18 7QH, UK

Corresponding author: Dr Loretta Ford. Email: Loretta.Ford{at}swbh.nhs.uk

Background: We have examined the effect of delayed sample separation on serum creatinine measurement using the kinetic Jaffe method and estimated glomerular filtration rate (eGFR), and the impact this can have on chronic kidney disease (CKD) staging.

Methods: In a preliminary study clotted samples were left at room temperature for up to 48 h prior to centrifugation and serum creatinine measurement on a Roche modular analyser. A larger study then used paired clotted samples separated at baseline (30 min) and after 24 h at room temperature. To determine the effect on CKD staging, eGFR was calculated using the simplified [4-v] Modification of Diet in Renal Disease formula.

Results: Preliminary study. A significant increase in creatinine concentration (P < 0.001) occurred after a 16 h delay in sample separation. By 48 h the mean increase in creatinine was 29% (range 21–63%).

Twenty-four hour delay study. The mean increase in creatinine for 113 outpatient samples after delaying sample separation by 24 h was 11%, and exhibited considerable individual variation (range 2–87%). CKD staging for 32% of the group changed, 26% from stage 1 to 2 and 6% from stage 2 to 3.

Conclusions: Delay in sample separation affects the creatinine measurement using the Roche kinetic Jaffe reaction, and can result in the misclassification of CKD staging. Laboratories using the kinetic Jaffe method should not report creatinine results where there has been a delay in separation. This advice should also be reflected in practice guidelines.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?