Blood Collection Tube Top Colors
Click on the stopper to get additional information
Order of the Draw
To prevent contamination of tubes with additives from other tubes it is important to draw the tubes in a SPECIFIC order called "the order of the draw". For example, if the additive in the purple stopper tube contaminates the green stopper tube this would cause a falseley decreased calcium and increased potassium. Please, JUST DO IT. The sequence of collection of evacuated tubes in a multi-draw should be in this order:
http://www.pathology.med.umich.edu/bloodbank/faqs.html - has the following picture. Visit their website as it has some other nice pictures and explanations.