Influence of sample type and storage conditions on soluble CD40 ligand assessment.
BACKGROUND
Several studies have consistently shown that soluble CD40 ligand (sCD40L) concentrations are increased in patients with acute coronary syndromes and can serve as a biomarker for risk stratification. However, few data are available on preanalytic conditions that impact sCD40L values. Thus, the aim of our prospective study was to evaluate the impact of sampling techniques and storage conditions on sCD40L concentrations.


METHODS
We included a total of 30 patients with no, stable, or unstable coronary heart disease. Blood samples were collected in gel-filled tubes without additives, in EDTA-filled tubes, and in citrate-filled tubes and were kept at various storage conditions.


RESULTS
Median (interquartile range) sCD40L values at baseline were higher in serum samples [5.29 (3.89-6.33) microg/L] than in either EDTA plasma [0.78 (0.39-1.12) microg/L; P <0.001] or citrate plasma [0.37 (0.22-0.51) microg/L; P <0.001]. Serum values increased with delayed processing [7.94 (5.97-9.62) microg/L after 1.5 h (P <0.001) vs baseline; 10.55 (7.58-11.55) microg/L after 3 h (P <0.001) vs baseline]. However, after centrifugation, sCD40L values remained stable for all 3 sample types.


CONCLUSIONS
Plasma, but not serum, samples are appropriate for sCD40L measurements. In general, preanalytic conditions are critical in the assessment of sCD40L concentrations and thus should be carefully considered for future studies.
Weber
Michael
M
Kerckhoff Heart Center, Department of Cardiology, Bad Nauheim, Germany. M.Weber@kerckhoff-klinik.de
Rabenau
Birgitt
B
Stanisch
Michael
M
Elsaesser
Albrecht
A
Mitrovic
Vesselin
V
Heeschen
Christopher
C
Hamm
Christian
C
D015415:Biomarkers / Q000097:blood; D001800:Blood Specimen Collection; D023201:CD40 Ligand / Q000097:blood*; D003327:Coronary Disease / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010949:Plasma; D011446:Prospective Studies; D044967:Serum; D012995:Solubility
D015415:Biomarkers; D023201:CD40 Ligand