You should be aware of the order of draw in which you draw the samples.
This is crucial to ensure the minimum interference of the sample for analysis and is recommended by the National Committee for Clinical Laboratory Standards.
The Gauge of the Needle
Regardless of which system you use, the colour coding of the gauge of the needle will remain the same.
The only needles used in venepuncture are:
•GREEN 21g Needle: Adults for general use.
•BLACK 22g Needle: Older or younger adults who might not have had a blood test or have small veins.
•BLUE 23g Needle: Older adults and children.