Analytical characterization and clinical evaluation of an enzyme-linked immunosorbent assay for measurement of afamin in human plasma.
Author(s): Dieplinger B, Egger M, Gabriel C, Poelz W, Morandell E, Seeber B, Kronenberg F, Haltmayer M, Mueller T, Dieplinger H
Publication: Clin Chim Acta, 2013, Vol. 425, Page 236-41
PubMed ID: 23981841 PubMed Review Paper? No
Purpose of Paper
Conclusion of Paper
Studies
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Study Purpose
The purpose of this study was to determine the effects of patient age and gender, time of blood collection relative to menstrual cycle and eating, plasma storage temperature and duration, and using serum instead of plasma for the quantification of afamin. The correlation of afamin levels with levels of other clinical chemistry analytes was also investigated. Blood was collected into plain or EDTA polyethylene terephthalate glycol tubes and centrifuged to obtain serum and plasma respectively. To determine the effects of fasting, blood was collected at 7 AM (overnight fast), 11 AM, and 2 PM, with meals immediately following the 7 AM and 11 AM blood draws. To determine the effects of diurnal variation, blood was collected from non-fasting women every 4 h for a 24 h period starting at 8 AM.
Summary of Findings:
Afamin levels were stable in plasma stored for up to 24 h at room temperature or 48 h at 4 degrees C, but levels declined with further storage at room temperature or 4 degrees C. In contrast, storing plasma at -20 or -80 degrees C had no effect on afamin levels. Patient age, gender, estimated glomerular filtration rate (eGFR), collecting serum rather than plasma, fasting status, time of collection, and day of menstrual cycle had no effects on levels of afamin. Heart failure, pneumonia and sepsis led to decreased levels of afamin compared to healthy individuals or those with kidney disease or chronic obstructive pulmonary disease. Afamin levels were modestly and negatively correlated with levels of CRP (r= -0.463, p<0.001) and IL-6 (r= -0.471, p< 0.001), weakly negatively correlated with levels of PCT (r= -0.234, p= 0.019), weakly associated with albumin levels (r=0.269, p= 0.007) and very weakly and negatively associated with levels of BNP(r= -0.187, p= 0.063).
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Cardiovascular Disease
- Chronic Obstructive Pulmonary Disease (COPD)
- Pneumonia/Respiratory Infection
- Normal
- Other diagnoses
Platform:
Analyte Technology Platform Protein ELISA Protein Clinical chemistry/auto analyzer Peptide Clinical chemistry/auto analyzer Small molecule Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Preaquisition Patient gender Female
Male
Preaquisition Patient age 18-24 years
25-34 years
35-44 years
45-54 years
55-65 years
Preaquisition Diagnosis/ patient condition Heart failure
Pneumonia
Sepsis
Renal disease
Chronic obstructive pulmonary disease
Healthy
Biospecimen Aliquots and Components Blood and blood products Plasma
Serum
Biospecimen Acquisition Time of biospecimen collection 7 AM (after fast)
11 AM (after eating)
2 PM (after eating)
8 AM
12 PM
4 PM
8 PM
12 AM
4 AM
Day 3-5 of menstrual cycle
Day 10-12 of menstrual cycle
Day 21-23 of menstrual cycle
Storage Storage duration 0 h
4 h
12 h
24 h
48 h
72 h
1 week
1 month
6 months
1 year
Storage Storage temperature Room temperature (18-25 degrees C)
4 degrees C
-20 degrees C
-80 degrees C
Preaquisition Biomarker level <90 mL/min eGFR
>90 mL/min eGFR