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.
FLOW
The semaglutide renal outcome trial in type 2 diabetes with chronic kidney disease.
What the outcome trials measured in the kidney
Asymptomatic pancreatic enzyme elevation is common on treatment and is not pancreatitis. The distinction is clinical, not biochemical.
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.
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.
What the trials monitored, and what that implies about routine practice
What the pivotal programmes measured and how often, which is a more defensible template than most published monitoring schedules.
Measuring more frequently generates more flags and not more information
What the pivotal programmes measured and how often, which is a more defensible template than most published monitoring schedules.
Vitamin D, adiposity, and a volume-of-distribution problem
What the trials measured, which in the case of micronutrients is very little.
What the upper limit of normal for ALT should be, and why it is not
What the renal and hepatic outcome programmes actually measured, and over what duration.
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.
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.
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.
Why your laboratory interval differs from the one in the textbook
A flag is a probability statement about a population. It is not a statement about the person holding the printout.
EGFR, cystatin C, and the check on the check
The reference interval for alanine aminotransferase in most laboratories is derived from a population that included people with undiagnosed fatty liver.
Why your laboratory interval differs from the one in the textbook
A twelve-analyte panel in a perfectly healthy person has roughly even odds of producing at least one flagged result.
A reference interval is not a target, and a result outside one is not a diagnosis
Almost every misreading of a laboratory panel is a misunderstanding of what a reference interval is and how much a result has to move before the movement means anything.
Why your laboratory interval differs from the one in the textbook
A flag is a probability statement about a population. It is not a statement about the person holding the printout.
Falling ferritin is not always falling iron
The panel drawn during a week of vomiting is measuring the vomiting.
Vitamin D, adiposity, and a volume-of-distribution problem
Reduced intake is a plausible mechanism for deficiency. Reduced absorption is not, and the two are conflated in most of the advice.
Why your laboratory interval differs from the one in the textbook
The arithmetic of the reference change value, worked for the analytes that matter here.