April 1, 1987Journal of Hypertension
Radio-lmmunoassay for Plasma Alpha Human Atrial Natriuretic Peptide: A Comparison of Direct and Pre-Extracted Methods
Why the study?
Does pre-extraction of plasma using C18 reverse phase columns improve the accuracy of radio-immunoassay for measuring atrial natriuretic peptide compared to direct assay?
Population
Normal subjects, patients with renal failure, and patients with cardiac dysfunction.
Comparison
Pre-extraction of atrial natriuretic peptide… vs Direct radio-immunoassay
Design
Other
Authors
Discussion
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Member takes
Implication
Pre-extraction may enhance ANP assay accuracy by reducing interference; leaves open whether it alters clinical interpretation in cardiorenal disease.
Key Points
- To compare direct radio-immunoassay with C18 reverse-phase pre-extraction for measuring plasma alpha human atrial natriuretic peptide (ANP) in healthy individuals and patients with cardiorenal disease.
- Measured plasma ANP via direct radio-immunoassay and following pre-extraction using C18 reverse-phase columns.
- Evaluated healthy volunteers (including 8 subjects receiving an intravenous 0.9% NaCl infusion), patients with cardiac dysfunction, and patients with renal failure (including end-stage disease undergoing hemodialysis).
- Investigated sources of assay discrepancy using gel filtration chromatography.
- Pre-extracted assays demonstrated good overall correlation with direct assays but yielded significantly lower absolute values due to the removal of interference from platelets and an unidentified plasma component.
- Plasma ANP concentrations were elevated in cardiac and renal failure, decreased following renal dialysis, and rose in healthy volunteers challenged with an intravenous isotonic fluid load.
Structured PICO
Does pre-extraction of plasma using C18 reverse phase columns improve the accuracy of radio-immunoassay for measuring atrial natriuretic peptide compared to direct assay?
P
Population
Normal subjects (including 8 volunteers receiving intravenous infusion of 0.9% NaCl solution), patients with renal failure (including end-stage disease undergoing renal dialysis), and patients with cardiac dysfunction.
I
Intervention
Pre-extraction of atrial natriuretic peptide (ANP) from plasma using C18 reverse phase columns prior to radio-immunoassay
C
Comparator
Direct radio-immunoassay
O
Outcome
Plasma atrial natriuretic peptide (ANP) concentrationsurrogate
Pre-extraction of plasma using C18 columns eliminates interference in ANP radio-immunoassay, providing more accurate measurements, particularly within the normal range.
Cite This Study
Richards et al. (1987) studied this question.