A reference interval is not a target, and a result outside one is not a diagnosis
Two sources of noise sit under every number: how reproducible the assay is, and how much the analyte varies within the same person on the same day.
Bloodwork
Laboratory panels before, during and after treatment, and which changes are findings rather than artefacts.
What the trials monitored, and what that implies about routine practice
Timing is the whole of the post-cessation panel: draw it too early and it measures the treatment period.
A reference interval is not a target, and a result outside one is not a diagnosis
The arithmetic of the reference change value, worked for the analytes that matter here.
Micronutrient monitoring: which panel, how often, and on whose evidence
A monitoring schedule requires evidence about incidence. For this population, that evidence does not exist.
EGFR, cystatin C, and the check on the check
What the renal and hepatic outcome programmes actually measured, and over what duration.
What a low result means when intake has halved
Reduced intake is a plausible mechanism for deficiency. Reduced absorption is not, and the two are conflated in most of the advice.
Which results are findings and which are consequences of the weight loss
A substantial proportion of the abnormal results generated during rapid weight loss are consequences of the weight loss rather than findings about the person.
Measuring more frequently generates more flags and not more information
The argument for a baseline panel is that it makes every subsequent result interpretable. The argument against frequent monitoring is that noise accumulates faster than…
A guide to the results that will resolve themselves
A substantial proportion of the abnormal results generated during rapid weight loss are consequences of the weight loss rather than findings about the person.
Reading HbA1c in the presence of anaemia
HbA1c integrates roughly three months of glycaemia with the most recent weeks weighted most heavily. Almost every misreading of it is a misreading of that weighting.
A reference interval is not a target, and a result outside one is not a diagnosis
A twelve-analyte panel in a perfectly healthy person has roughly even odds of producing at least one flagged result.
Fructosamine, glycated albumin, and the shorter window nobody orders
The alternatives with shorter windows, what they measure, and why they are rarely ordered.
The out-of-range flag is a statistical convention with a printer attached
A flag is a probability statement about a population. It is not a statement about the person holding the printout.
What a low result means when intake has halved
Reduced intake is a plausible mechanism for deficiency. Reduced absorption is not, and the two are conflated in most of the advice.
HbA1c and its lag: what a result three months old is telling you
The assay is not the problem. The interpretation of a lagging integral as a current measurement is the problem.
What the trials monitored, and what that implies about routine practice
The argument for a baseline panel is that it makes every subsequent result interpretable. The argument against frequent monitoring is that noise accumulates faster than…
The out-of-range flag is a statistical convention with a printer attached
Two sources of noise sit under every number: how reproducible the assay is, and how much the analyte varies within the same person on the same day.
What the outcome trials measured in the kidney
Estimated glomerular filtration rate is a calculation with muscle mass in the denominator of its assumptions. In this population that matters.
What a low result means when intake has halved
Micronutrient guidance for this drug class is borrowed almost entirely from post-bariatric surveillance, where the anatomy is different and the deficiency mechanisms are not…
A reference interval is not a target, and a result outside one is not a diagnosis
Two sources of noise sit under every number: how reproducible the assay is, and how much the analyte varies within the same person on the same day.