Clinical Relevance of Biological Variation of B-Type Natriuretic Peptide

Biological and Analytical Variability of a Novel High-Sensitivity Cardiac Troponin T Assay

“…Some researchers have disputed the utility of biological variation for determining when analytically, and thus likely clinically, significant serial changes occur for other biomarkers (24,25 ). The results from our study should be verified in various patient populations.…”

“…Until this other approach is tested, we would advocate for the serial determination of hscTnT using a minimum change of 85% over a 6-h period to detect a ␦ value. Biological variation using hscTn could also be used in patients with stable heart disease such as stable coronary artery disease or congestive heart failure, as advocated by other groups (25,26 ). However, such studies must be interpreted cautiously due to the high likelihood for a variety of interceding events such as angina or heart failure that could induce the release of cTn.…”

Short- and Long-Term Biological Variation in Cardiac Troponin I Measured with a High-Sensitivity Assay: Implications for Clinical Practice

“…Therefore, minor changes in serial results will not be meaningful, as one of us recently suggested for hsCRP (31 ). Other investigators have challenged the utility of biological variation for measuring significant serial changes for hsCRP and BNP (32,33 ). The cTnI results for monitoring cardiac disease appear to be appreciably different from those for the other markers of chronic cardiac disease.…”

Reference Change Values for Brain Natriuretic Peptides Revisited

“…Hyperammonemia can result from hepatic failure, enzymatic deficiencies of the urea cycle or defects in ornithine transport [e.g., HHH syndrome (hyperornithinemia, hyperammonemia, hyperhomocitrullinuria)], or it may be secondary to other organic acidopathies (3 ). The hyperammonemia observed in methylmalonic acidemia is thought to arise because accumulated propionyl CoA interferes with formation of N-acetylglutamate, an obligatory activator of carbamyl phosphate synthase, the initial step in urea synthesis (4 ).…”