[Explainer] which labs are worth repeating quarterly and which are theatre
which labs are worth repeating quarterly and which are theatre. That is the post. The justification is underneath.
Panicked about a single result, posted here, got told to repeat it, repeated it, and it was fine.
Tracked triglycerides against the weight trend for a year. The correlation was much weaker than I expected and that was worth knowing.
Draw at the same point in the week now, fasting, same lab. The noise dropped enormously once I standardised.
That is everything I have. The rest is opinion and I have tried to keep it out.
best — the order this archive was captured in
Left up. It is a question about how to compare panels, not a request for interpretation.
Do you have a baseline from before you started?
the trend line matters more than any single value
Reference intervals are typically the central 95% of a reference population. By construction one person in twenty falls outside one on any given test without anything being wrong.
bring the numbers to someone qualified to read them
same lab, same conditions, or you are comparing noise
do not change three things and then read the panel
hydration status moves a surprising number of markers
one measurement is a point, two is a line, three is a trend
How to make a panel worth comparing, which is most of the value people leave on the table.
Standardise the conditions: same lab, same fasting state, same rough time of day, same point in the week, similar hydration. Take a baseline before you change anything. Repeat any surprising value before acting on it. Change one thing at a time if you want to attribute anything to it.
Do that and a year of panels is a trend. Skip it and a year of panels is a collection of unrelated mornings, which is what most of the alarmed posts here are actually describing.
That comparison crosses two labs with different assays. The difference you are describing may be the method.
a single ALT outside range is a reason to repeat, not to panic
My ferritin moved and I spent a fortnight convinced I knew why. The repeat six weeks later was back in range and I had changed nothing.
Not convinced by the attribution. Weight loss alone moves that marker and you have no way to separate the two.
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