The order of draw is the sequence for filling blood collection tubes during one venipuncture. Following it prevents additive carryover between tubes, which can skew coagulation, chemistry, and hematology results. The standard CLSI order is: blood culture, light blue (sodium citrate), red or gold serum, green (heparin), lavender (EDTA), then gray.

A common memory aid is “Boys Love Ravishing Girls Like Gina.” When drawing only a light blue (coagulation) tube with a butterfly needle, use a small discard tube first so the citrate tube fills completely for accurate PT/PTT results.

Shop blood collection tubes and butterfly needles at Mudomed.