[Discussion] the ALT advice in here is 2 years out of date
the ALT advice in here is 2 years out of date. Making the case below, and I expect to lose some of it in the comments.
To save the first four comments: 2 years.
My ApoB moved and I spent a fortnight convinced I knew why. The repeat six weeks later was back in range and I had changed nothing.
Tracked triglycerides against the weight trend for a year. The correlation was much weaker than I expected and that was worth knowing.
Not medical advice, obviously, and nothing here is approved for human use. One person with a spreadsheet.
best — the order this archive was captured in
Why so many single values look alarming and turn out to be nothing.
A reference interval is built to contain about 95% of a healthy reference population, so one test in twenty falls outside one by construction. Add biological variation, assay imprecision, fasting state and time of day, and a genuinely stable person will produce occasional out-of-range results.
That is why repeat testing before acting is standard. Regression to the mean handles most of it. None of which means an out-of-range value should be ignored — it means it should be repeated and taken to somebody who can put it in context, which is emphatically not a ranked feed.
ApoB is the one worth adding if you only add one
Compared two draws across two labs and spent a week worrying before finding out the assays were different.
nothing on this board interprets your results for you
That is a non-fasting value and the interval you are comparing it against is a fasting one.
ask whether the lab changed its assay between your two draws
Added ApoB to the panel after a thread here. It told me something the standard lipid panel had been hiding.
Have you taken this to whoever ordered it?
Same lab as the previous draw?
assay method matters, especially between different labs
Brought the whole set to my clinician rather than one flagged value. Completely different conversation.
same lab, same conditions, or you are comparing noise
one measurement is a point, two is a line, three is a trend
same lab, same conditions, or you are comparing noise
Agreed — and standardising the draw conditions is the cheapest improvement available.
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.
lab reference ranges are not treatment targets
a single ApoB outside range is a reason to repeat, not to panic
the trend line matters more than any single value
a single ApoB outside range is a reason to repeat, not to panic
Disagreeing with this bit: that change is confounded by the weight loss itself and cannot be attributed.
hydration status moves a surprising number of markers
What did the repeat show?
weight loss itself moves several of these independently
baseline before you start is worth more than any later panel
Fasting or not, and what time of day?
Yes — same lab, same fasting state, same rough time of day, or the comparison is doing nothing.
Disagree with reading anything into that. One value, one morning, and you changed two other things in the same window.
- 1Brought the whole set to my clinician rather than one flagged value.…14 comments in this branch · started by u/signe_grimaldi
- 2Why so many single values look alarming and turn out to be nothing. A…9 comments in this branch · started by u/coldchain_karen