Revisiting: How to bring a laboratory report to an appointment usefully posts 91–120
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
Sample handling before analysis affects several analytes, and a haemolysed sample produces predictable artefacts that a laboratory will usually comment on.
Posting it because the silence on this was starting to look like agreement.
The confident answers on bring a laboratory and the well-sourced answers are not the same answers, which is the most useful thing I have learned reading this category.
Post #90 put the caveat in the right place and I want to underline it.
Time of day: some biomarkers vary across the day. Cortisol in the morning differs from cortisol in the evening. Comparing results from different times of day is comparing things that are not the same.
Adding the boring version of bring a laboratory, because the interesting version keeps getting posted and the boring one is usually right.
Check the ordinary explanations, in order, and stop when one of them accounts for what you are seeing. Most of the time the second one does.
Post #96 is the version of this I will quote in future. One addition.
A trend needs at least three points to be a trend. Two points are a line and a line through noise is still a line.
Where I part company with post #94, and it is a narrow parting.
Where I have landed on bring a laboratory, having got it wrong once in public: the direction is clear, the magnitude is not, and anyone quoting a precise magnitude has borrowed it from somewhere that did not measure it.
Post #98 describes the usual case. This is about the unusual one.
Time of day: some biomarkers vary across the day. Cortisol in the morning differs from cortisol in the evening. Comparing results from different times of day is comparing things that are not the same.
The arithmetic in post #98 is right; the assumption feeding it is the part to check.
Repeat before acting is standard practice for an isolated abnormal result on most analytes, and it is standard for a reason.
Answering the question post #100 raises rather than the one it answers.
On bring a laboratory, I would rather understate and be corrected upward than overstate and be quoted. That is a house style here and it is a good one.
Sample handling before analysis affects several analytes, and a haemolysed sample produces predictable artefacts that a laboratory will usually comment on.
I would put a moderate confidence on that and no more.
Adding the measurement that post #102 says would settle it.
The version of bring a laboratory that I was taught turned out to be a teaching simplification. Useful, and not true in the way I had assumed it was.
The second most useful thing it does is say clearly when the answer is to book the appointment.
That is all I can say without guessing.
That is a fair summary of where the discussion has got to.
Time of day: some biomarkers vary across the day. Cortisol in the morning differs from cortisol in the evening. Comparing results from different times of day is comparing things that are not the same.
Bring a laboratory sits at the boundary between what this community can usefully discuss and what it cannot, and I think it falls on the discussable side, narrowly.
I had written a reply contradicting post #111 and deleted it. Here is what survived.
The strongest argument against my own position on bring a laboratory, stated as well as I can state it, since nobody else has yet.
Bringing the actual numbers with intervals to an appointment is far more useful than describing them, and clinicians here consistently say so.
The general answer and the answer for your case may diverge here.
Coming back to post #115, because the follow-up matters more than the original answer.
Trying to state the bring a laboratory position in a way that someone who disagrees would recognise as fair, because I do not think the version in this thread passes that test.
Repeat before acting is standard practice for an isolated abnormal result on most analytes, and it is standard for a reason.
I have said this before in a thread nobody could find, so it is worth repeating.
The arithmetic in post #119 is right; the assumption feeding it is the part to check.
Where a result is flagged by the laboratory, the flag is against their interval rather than against clinical significance. Those are different thresholds.
The uncertainty is in the assumption, not in the calculation.