Pre-analytical effects of blood sampling and handling in quantitative immunoassays for rheumatoid arthritis.

Author(s): Zhao X, Qureshi F, Eastman PS, Manning WC, Alexander C, Robinson WH, Hesterberg LK

Publication: J Immunol Methods, 2012, Vol. 378, Page 72-80

PubMed ID: 22366959 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of specimen type (serum versus plasma) and storage of serum on the clot overnight on levels of autoantibodies and proteins in specimens from rheumatoid arthritis patients. Serum specimens were processed by one of two protocols. The first method included overnight shipment of uncentrifuged specimens on the clot, in serum separator transport tubes (SST), at ambient temperatures, centrifugation, aliquoting, and storage at -80 degrees C. The second method included centrifugation of specimens after 30-45 minutes at room temperature, overnight shipment at 2-8 degrees C, aliquoting, and storage at -80 degrees C.

   Summary of Findings:

   All autoantibody biomarkers had no more than an 8% median difference in levels between serum and plasma specimens and were very strongly correlated between specimen type (r=0.98-1.00). When centrifugation of serum specimens was delayed overnight (and specimens were transported at ambient temperatures), 6 of 8 autoantibody biomarkers had no more than a 10% median difference in levels compared to those centrifuged after 30-45 min and then shipped at 2-8 degrees C, however cApoE and cFil showed median differences between the two protocols of 16 and 24%, respectively. The majority of protein biomarkers were measured at higher levels in serum than in plasma, but 7 out of 12 had no more than a 12% median difference in levels and were very strongly correlated (r=0.99-1.00) between serum and plasma specimens. The larger median differences in protein biomarker expression levels between serum and plasma were 18% for resistin (r=0.91), 19% for vascular cell adhesion protein 1 (VCAM-1) (r=0.97), 23% for matrix metalloproteinase-1 (MMP-1) (r=0.74), 51% for EGF (r=0.33), and 55% for VEG-F (r=0.87). The majority of protein biomarker levels were very susceptible to delayed centrifugation with median increases in Ykl-40, VEG-F, resistin, IL-6, and EGF of 83, 112, 235, 329, and 416%, respectively, when centrifugation was delayed overnight.

   Biospecimens

   • Bodily Fluid - Plasma
   • Bodily Fluid - Serum
   • Bodily Fluid - Blood

   Preservative Types

   • Frozen

   Diagnoses:

   • Rheumatoid Arthritis

   Platform:

   Analyte	Technology Platform
   Protein	Immunoassay
   Glycoprotein	Immunoassay

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Aliquots and Components	Blood and blood products	Plasma Serum
   Storage	Time at room temperature	30-45 min Overnight
   Storage	Between site transportation method	Mailed
   Storage	Specimen transport duration/condition	In SST at ambient temperature After separation at 2-8 degrees C
   Biospecimen Aliquots and Components	Centrifugation	Centrifugation delays investigated

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