A comparison of serum versus heparinized plasma for routine chemistry tests.

Author(s): Lum G, Gambino SR

Publication: Am J Clin Pathol, 1974, Vol. 61, Page 108-13

PubMed ID: 4809144 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 analyzing serum rather than plasma and analysis method on clinical chemistry analytes. Serum and plasma were separated within 2 h of blood draw and assayed immediately following separation or stored for less than 24 h at 4 degrees C prior to analysis.

   Summary of Findings:

   A significant and clinically important elevation in serum potassium was found compared to plasma levels using both the SMA 6/60 analyzer (p<0.005) and the flame photometer (p<0.005), but the degree of elevation depended on analysis method. There were significantly and clinically relevant higher levels of total protein in plasma than in serum (p<0.005). Significant, but clinically irrelevant elevated levels of albumin, alkaline phosphatase, inorganic phosphorous, sodium, triglyceride and uric acid levels were found in serum compared to plasma using one or more methods of analysis (all p<0.025). There were no differences between serum and plasma when levels of chloride were measured coulometrically, but when the Technicon SMA 6/60 autoanalyzer was used, significantly more chloride was found in serum than in plasma (p<0.01). Similarly, there were no differences between serum and plasma when LD was measured using the LKB 8600 reaction rate analyzer, but serum had higher LD levels when the Technicon SMA 12/60 was used. Cholesterol was higher in unextracted plasma than in serum (p<0.005), but following plasma extraction, cholesterol levels were higher in serum than in plasma (p<0.05). Alanine aminotransferase (ALT), aspartate aminotransferase (AST), amylase, bilirubin, blood urea nitrogen (BUN), calcium, carbon dioxide, creatinine phosphokinase, creatinine, glucose levels were not significantly different between plasma and serum specimens.

   Biospecimens

   • Bodily Fluid - Serum
   • Bodily Fluid - Plasma

   Preservative Types

   • None (Fresh)

   Diagnoses:

   • Normal
   • Not specified

   Platform:

   Analyte	Technology Platform
   Protein	Clinical chemistry/auto analyzer
   Small molecule	Clinical chemistry/auto analyzer
   Electrolyte/Metal	Flame emission photometry
   Electrolyte/Metal	Coulometer
   Electrolyte/Metal	Clinical chemistry/auto analyzer
   Gas	Clinical chemistry/auto analyzer
   Carbohydrate	Clinical chemistry/auto analyzer
   Steroid	Clinical chemistry/auto analyzer
   Lipid	Clinical chemistry/auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Aliquots and Components	Blood and blood products	Plasma Serum
   Clinical chemistry/auto analyzer Specific	Technology platform	Technicon SMA 12/60 autoanalyzer Technicon SMA 6/60 autoanalyzer LKB 8600 reaction rate analyzer Abbot Bichromatic analyzer 100 I.L. flame photometer Spectrophotometer Coulometer

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