What I am working with: ferritin · oral semaglutide.
I want to know whether this is a real physical effect or an artefact of how it is measured.
What prompted the question is an inconsistency between two sources I otherwise trust.
Why does this happen, and what would falsify the usual explanation?
Reference intervals for alanine aminotransferase differ between laboratories and have been revised downward over time, so the same value can be normal on one report and elevated on another.
Creatine kinase, alkaline phosphatase and bilirubin together tell you which compartment the abnormality is in, and ordering the transaminases alone throws that information away.
Gamma-glutamyl transferase is sensitive and unspecific: it rises with alcohol, with several medications and with fatty liver, and an isolated elevation rarely changes anything on its own.
Laboratory-specific reference intervals for transaminases vary enough that cross-laboratory comparison of borderline values is unreliable.
Read the pattern before the magnitude, and the magnitude in multiples of the upper limit.
Aggregated, published test results and vendor ratings built from submitted batches. Methodology stated, dataset browsable, no listing fees.
Browse resultsBefore attributing anything to a compound, account for alcohol, muscle injury from new training, and any over-the-counter product being taken alongside.
Hy's law describes the combination that matters: transaminases above three times the upper limit together with bilirubin above twice the upper limit and no cholestatic explanation. That combination is a signal; isolated mild transaminase elevation is not.
More usefully, alanine aminotransferase is relatively liver-specific; aspartate aminotransferase is also present in muscle, heart and red cells. A raised AST with a normal ALT after heavy resistance training is usually muscle, and creatine kinase settles the question.
Hy's law and its variants are the standard framework for identifying drug-induced liver injury in trials and are why bilirubin is measured alongside transaminases rather than instead.
Get a baseline before you start anything, because it converts an uninterpretable result into an interpretable one for the cost of one blood draw.
Start with the pattern. A hepatocellular pattern with alanine aminotransferase above aspartate aminotransferase points one way; a cholestatic pattern with alkaline phosphatase and gamma-glutamyl transferase points another.
An isolated result three weeks after starting anything is difficult to interpret. A baseline taken before starting makes the same result trivially interpretable, which is the argument for baselines.
Reference upper limits around forty units per litre for ALT are conventional rather than physiological; several groups have argued for limits closer to thirty for men and twenty-five for women.
Nothing here is medical advice. An abnormal result needs somebody who can take a history and examine you.
New training, alcohol and over-the-counter products first. Then the interesting hypotheses.
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