Order of Draw and Tube Guide
Venous order of draw is blood cultures, light blue citrate, serum, heparin, EDTA, then gray fluoride/oxalate, the same for tube holder, syringe or butterfly draws.
Venous order of draw (CLSI GP41)
| order | tube / closure colour | additive | inversions | typical use | why this position |
|---|---|---|---|---|---|
| 1 | Blood culture bottles or tube | Culture media (bottle) | Per bottle manufacturer | Blood cultures (detect bacteria/fungi in blood) | Drawn first to keep the sample sterile and free of additive carryover |
| 2 | Light blue | Buffered sodium citrate (3.2%) | 3-4 | Coagulation tests (e.g., PT/INR, aPTT) | Only blood cultures, glass non-additive serum tubes, or plastic serum tubes without clot activator may be drawn before it; clot activator interferes with coagulation testing |
| 3 | Red (plastic, clot activator); gold or red/gray speckled (SST, clot activator + gel); orange (thrombin clot activator) | Clot activator, with or without gel; glass red tube has no additive | 5 (plastic serum, SST); 0 (glass red, no additive) | Serum chemistry and serology | Serum tubes follow citrate so clot activator cannot reach the coagulation tube |
| 4 | Green (dark green, light green, speckled green) | Heparin (lithium or sodium), with or without gel | 8 | Plasma chemistry | Heparin carryover can falsely affect coagulation tests, so it comes after citrate |
| 5 | Lavender (also pink, pearl/white with gel) | EDTA (K2 or K3), with or without gel | 8 | Hematology, e.g., CBC; K2EDTA is also used for routine immunohematology (blood bank) | EDTA carryover alters chemistry and coagulation results (e.g., falsely high potassium, falsely low calcium), so it comes after those tubes |
| 6 | Gray | Sodium fluoride (glycolytic inhibitor) with potassium oxalate or Na2EDTA | 8 | Glucose determinations | Last in the CLSI order; fluoride and oxalate carryover could alter results in other tubes |
The order is the same whether you use a tube holder, a syringe, or tubes evacuated at the time of collection (CLSI).
For tubes not on this list, place them according to whether their additive could alter results in the next tube (CLSI).
Inversions are BD counts: citrate 3-4, plastic red and SST 5, glass red 0, heparin, EDTA and gray 8 (BD Vacutainer Tube Guide reproduced on PMC7158162; the same BD counts are tabulated in the Croatian national venous sampling recommendations, PMC3900082, Table 3). Greiner Bio-One tubes use different counts. Always follow the inversion count printed by the tube manufacturer.
Invert gently (180 degrees and back). Do not shake.
Preview only. The full sheet also covers: Key rules to remember.
Sources
- Order of Blood Draw Tubes and Additives (summary of CLSI GP41, Collection of Diagnostic Venous Blood Specimens) · Clinical and Laboratory Standards Institute (CLSI)
- Laboratory Diagnosis and Test Protocols, Table 5-1 'Venous Blood Collection Tube Guide' (reproduced from the BD Vacutainer Tube Guide). In: Kirk & Bistner's Handbook of Veterinary Procedures and Emergency Treatment (PMC7158162) · Elsevier via PubMed Central
- Nikolac N, et al. Croatian Society of Medical Biochemistry and Laboratory Medicine: national recommendations for venous blood sampling. Biochem Med (Zagreb). 2013;23(3):242-254 (based on CLSI H3-A6) · Biochemia Medica via PubMed Central
- Clinical Nursing Skills, 10.4 Blood Sampling (CC BY-NC-SA; used for fact-checking only, no wording reused) · OpenStax, Rice University