Cap Color Blood Collection Tubes & Order of Draw

Vocabulary flashcards summarizing the cap colors, additives, uses, inversion counts, and order of draw for common blood collection tubes.

Blood Culture Tube (Yellow/Sterile Bottle)

Contains culture media; drawn FIRST with sterile technique; invert 3–4 times; used for microbiology blood cultures.

Light Blue Top Tube

Additive: Sodium citrate (anticoagulant); used for coagulation studies (PT, aPTT, D-dimer); invert 5 times; drawn after blood cultures.

Red Top Tube (Plain / Clot Activator)

Silicon-coated glass or clot activator plastic; yields serum; used for chemistry, serology; invert 5 times; drawn after light blue.

Gold / Tiger Top (SST) Tube

Serum Separator Tube with clot activator + gel barrier; used for routine chemistry panels; invert 5 times; drawn after red top.

Green Top Tube

Additive: Heparin (sodium, lithium, or ammonium); produces plasma; used for STAT chemistry tests; invert 8–10 times; drawn after SST.

Lavender / Purple Top Tube

Additive: K2 EDTA; preserves cellular components; used for hematology (CBC) and Hemoglobin A1C; invert 8 times; drawn after green top.

Pink Top Tube

Additive: EDTA; formulated for blood bank testing; used for blood group & cross-matching; invert 8 times; drawn with or after lavender.

Gray Top Tube

Additives: Sodium fluoride (glycolysis inhibitor) + potassium oxalate (anticoagulant); used for blood glucose & lactate; invert 8–10 times; drawn LAST.

Order of Draw (Vacutainer Method)

1) Blood culture ➜ 2) Light blue ➜ 3) Red ➜ 4) Gold/Tiger (SST) ➜ 5) Green ➜ 6) Lavender/Pink ➜ 7) Gray.

Tube Inversion Guidelines

Gentle, complete inversions mix additive with blood: 3–4× for cultures, 5× for citrate & clot-activator tubes, 8–10× for heparin, EDTA, and fluoride tubes to prevent clotting or glycolysis.