Within-person variation of plasma homocysteine and effects of posture and tourniquet application.

Author(s): Rasmussen K, Moller J, Lyngbak M

Publication: Clin Chem, 1999, Vol. 45, Page 1850-5

PubMed ID: 10508133 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 patient posture, tourniquet application, and folic acid supplementation on hematocrit and levels of Hcy, albumin, creatinine, and protein in plasma. 4 specimens were collected at a time. The first tube was thrown away, the second tube (heparin) was used to measure albumin and protein, the third tube (EDTA) was used for hematocrit, and the forth tube (heparin and sodium fluoride) was used for Hcy measurement. Plasma was stored at -20 degrees C until analysis.

   Summary of Findings:

   Supplementation with folic acid significantly decreased the average concentrations of Hcy in plasma. Between and within person variations in plasma Hcy concentrations were not significantly different between males and females and not altered by folic acid supplementation. After 30 minutes of supine rest, significant decreases in Hcy, albumin, hematocrit, and protein were observed compared to measurements taken from sitting patients. The plasma Hcy/albumin ratio was not significantly affected by patient posture. Hematocrit and concentrations of Hcy, albumin, and protein in plasma significantly increased when a tourniquet was applied for 3 min instead of about 15 sec during specimen collection. But again, the plasma Hcy/albumin ratio was not significantly affected by tourniquet application.

   Biospecimens

   • Bodily Fluid - Blood
   • Bodily Fluid - Plasma

   Preservative Types

   • Frozen

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   Small molecule	GC-MS
   Small molecule	Clinical chemistry/auto analyzer
   Protein	Clinical chemistry/auto analyzer
   Cell count/volume	Hematology/ auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Acquisition	Method of fluid acquisition	Tourniquet times compared
   Preaquisition	Patient gender	Female Male
   Preaquisition	Other drugs	0.2 mg folic acid twice daily for 20 days None
   Biospecimen Acquisition	Patient posture	Sitting Supine

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