Adding the clinical framing, because it changes how the question reads. Worth answering the question that was asked rather than the one behind it. The narrow version usually has an answer; the broad version usually does not, and answering the broad one is how a thread stops being useful.
BiostatsBrad said:One practical note: write down what you did and when, before you need it.
Coming at BiostatsBrad’s question from a different direction. The version of this that has an answer is narrower than the version being asked. Narrow it and it becomes tractable; leave it broad and the thread will produce nine confident and incompatible replies.
One concrete data point for the thread. Worth stating the units and the reference range whenever you post a number here. A large fraction of the apparent disagreement in these threads is two people using different units and both being right.
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Shop Reference StandardsA narrower follow-up, since the general answer is now clear:
What would you measure differently if you were starting again?
Moderator note: a post naming a supplier has been edited. Discuss suppliers in the review sections, not here. Report rather than reply if it drifts again.