Collection of Blood and Non-Blood Specimens
Venipuncture technique: apply the tourniquet, select and prepare the site, anchor the vein, insert bevel up at a shallow angle, and collect tubes in the correct order of draw. Know the standard order (blood cultures, then coagulation, serum, heparin, EDTA, glycolytic, and others per current guidelines) and why it matters-additive carryover. For capillary collection, warm the site, choose the side of the finger (not the tip or center), wipe away the first drop, and avoid squeezing hard to prevent hemolysis and tissue fluid dilution. Heel sticks for infants stay within the safe zones.
Non-blood specimens include urine (clean-catch midstream, first morning preferred for some tests), stool (with transport media for ova and parasites), sputum (deep cough, not saliva), and swabs. Traps include collecting urine from a bag in an ambulatory patient, using the wrong container or preservative, and delaying transport of urine or stool.
Worked rule of thumb: label at the point of collection, then transport promptly; if a specimen cannot be processed quickly, follow stability requirements (refrigerate or protect from light as specified). For blood cultures, collect before antibiotics when possible and use the specified volume per bottle-volume is a major determinant of sensitivity.
Specimen Processing and Transportation
Post-collection handling determines result validity. Know which tubes need centrifugation and within what time, which must be protected from light (bilirubin, some vitamins), and which must be kept on ice or at room temperature. Serum and plasma separators should be centrifuged per protocol; leaving cells in contact with serum too long can alter glucose, potassium, and other analytes. Coagulation specimens must be transported and processed per strict timing. Blood cultures go to the incubator promptly; do not refrigerate them.
Traps: centrifuging a tube that should not be spun, spinning before clotting is complete, re-spinning without policy, and transporting without secondary containment. Another trap is misreading stability: some tests require immediate delivery, others tolerate refrigeration, and freezing whole blood is usually wrong. Also know rejection criteria-unlabeled or mislabeled tubes, wrong tube type, insufficient volume, hemolysis, and clotted specimens.
Worked rule of thumb: if the label and requisition disagree or the tube is unlabeled, reject and recollect; never relabel a specimen you did not collect. Document rejections and notify the ordering provider when recollections are needed.
Transport: use leak-proof secondary containers, maintain temperature, and record chain of custody when required. Timely delivery is part of the test, not an afterthought.