Establishing Pragmatic Analytical Performance Specifications for Blood Beta-Hydroxybutyrate Testing.
Level 5 - mechanism / opinion, no new human data
Theoretical mathematical modeling of assay precision specifications based on clinical thresholds without human subject testing (level assigned by design analogy)
PubMed 36919618 · doi:10.1093/clinchem/hvad020
What was done
The authors modeled analytical performance specifications (APS) for blood beta-hydroxybutyrate (BOHB) assays using established diabetic ketoacidosis (DKA) clinical criteria. Specifications were derived from two requirements: distinguishing non-adjacent diagnostic categories (<0.6, 0.6 to 1.5, 1.6 to 2.9, and >=3 mmol/L) and confirming with high probability that a measured 0.5 mmol/L reduction during treatment reflects a true decline (>0 mmol/L), assuming zero analytical bias.
What was found
An analytical coefficient of variation (CV) of <21.5% was sufficient to distinguish non-adjacent DKA diagnostic categories with >99% certainty. In contrast, verifying that a measured 0.5 mmol/L decline at 3 mmol/L BOHB represented a true reduction required within-day CVs of 4.9% (optimal, 99% probability), 7.0% (desirable, 95% probability), and 9.1% (minimal, 90% probability). Allowable CVs were tighter at higher concentrations and wider at lower concentrations.
Why it matters
This study provides objective analytical precision benchmarks for point-of-care ketone meters and clinical laboratory assays to ensure reliable monitoring during DKA resuscitation.
Limits
The performance targets are based on theoretical statistical modeling rather than direct evaluation in clinical patient cohorts. The model assumed zero analytical bias and did not account for instrument-specific interferents, preanalytical variability, or between-lot variations in point-of-care test strips.
Cited by
- contradicts Diabetic ketoacidosis is characterized by blood ketone levels between 15 and 20 millimolar.