The out-of-range flag is a statistical convention with a printer attached
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.
Pancreatitis
Page 3 of 3 of this archive, newest first.
Falling ferritin is not always falling iron
A substantial proportion of the abnormal results generated during rapid weight loss are consequences of the weight loss rather than findings about the person.
Thiamine and the vomiting patient
Which markers are informative, which are confounded, and which move for reasons unrelated to nutrition.
What the upper limit of normal for ALT should be, and why it is not
Estimated glomerular filtration rate is a calculation with muscle mass in the denominator of its assumptions. In this population that matters.
HbA1c and its lag: what a result three months old is telling you
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.
The reference change value: the number that tells you whether a delta is real
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.
Reading HbA1c in the presence of anaemia
The alternatives with shorter windows, what they measure, and why they are rarely ordered.
Which results should be repeated before they are investigated
What the pivotal programmes measured and how often, which is a more defensible template than most published monitoring schedules.
A guide to the results that will resolve themselves
The panel drawn during a week of vomiting is measuring the vomiting.
The glycated haemoglobin assay, and the eight conditions that break it
The assay is not the problem. The interpretation of a lagging integral as a current measurement is the problem.