Testing the day after leg day
Hard training before a draw inflates creatine kinase, can bump ALT, AST and creatinine, and produces a panel that looks like organ trouble instead of a workout. Take one or two rest days before any panel that includes liver, kidney or muscle markers, and note recent training on the booking.
Hopping between labs and comparing the numbers
Different laboratories use different assay methods and reference ranges, so a small shift between two labs may be methodology, not biology. For anything you track over time — HbA1c, lipids, thyroid, ferritin — keep the same vendor and lab, and let the trend do the talking.
Booking a fasting draw for 4pm
A 4pm fasting appointment means either skipping lunch after a token breakfast — which is not a proper 12-hour fast — or fasting all day and producing a dehydrated, miserable sample. Outside Ramadan, fasting draws belong in the morning. If mornings are impossible, split the panel and do the non-fasting tests in the evening.