Final answer:
The order of draw for capillary collections is different from venipuncture due to the different compositions of capillary blood and venous blood. Capillary blood may contain more interstitial fluid, which can affect test results. Some tests also require capillary blood specifically.
Step-by-step explanation:
The order of draw for capillary collections is different from venipuncture because capillary blood and venous blood have different compositions. Capillary blood usually contains a higher concentration of interstitial fluid, which can contaminate the blood sample and affect the accuracy of the test results. To avoid this, phlebotomists collect capillary samples before venous samples. Additionally, some tests, such as glucose testing, require capillary blood specifically instead of venous blood.