The order of draw for a capillary blood collection is slightly different than the order of draw for a venous blood collection.
If capillary blood gases are ordered, they are drawn first to avoid introduction of room air as much as possible.
A specimen for blood count is collected before tubes containing other anticoagulants and additives. This is to ensure that the blood will not begin to clot before this specimen is collected; clots will affect the accuracy of the blood count. Blood specimens for newborn screening tests should be collected separately from a different site than the one for regular labs.
The following order of draw is commonly used:
Container | Additive | Use |
| Capillary blood gas collection tubes | Heparin | For capillary blood gas tests |
| Blood smear | --- | For hematology blood counts |
| Lavender top | EDTA | For hematology blood counts |
| Green top | Lithium heparin | Tests that require a heparinized plasma sample |
| __ | Other tubes containing anticoagulants | Varied |
| Red or gold top | Clot activator | Tests that require a serum sample |
| Red top | No additive | Tests that require a serum sample, but clot activator and/or gel may affect test |
