One of the most important skills a phlebotomist learns is called "following the order of draw." This is the uniform schedule you will use when collecting patient blood samples. The "long order" is the list of every possible blood test a lab could run, while the "short order" is the list of the more basic blood tests.
Here's what you should know about the order of draw:
Blood vials have distinctive stopper colors
Each blood sample tube type has a stopper that's a different color of the rainbow depending on the blood additive that is added to the vial. The additives are provided to aid in preserving the blood to run the required tests. You must collect samples from the colored vials in a very specific order.
You will always draw blood for any ordered blood cultures first, and you will have special bottles and tubes for that purpose. Think of "high culture" as the top of the heap to help you remember that these are your first-priority samples.
Next you draw light blue tubes for coagulation samples, red tubes for serum samples, green tubes for plasma samples, and so on. There are many different tests that may be run on blood, so you must spend significant study time memorizing the type of test each color designates and which additives correspond with the various colors.
The order of draw is very important
The blood-drawing protocol is important because of the way certain additives react with certain blood tests. When the needle pierces the stopper to begin filling it with blood, a tiny amount of additive from one tube may contaminate the next vial.
Contamination of the vial can skew the test results, making the sample useless or worse, leading health care professionals to misdiagnose or wrongly medicate the patient. For example, some additives contain potassium, which could falsely raise the potassium levels on a subsequent test if the vial is cross-contaminated. Following the order of draw eliminates any contamination problems, since the additives aren't harmful to the next sample when managed in the prescribed manner.
Every patient will have different tests run, so you won't do every test on every person. Depending on your job location, you may only draw blood for a few types of tests. But you must still follow the order of draw for the vials you are supposed to collect.
Tips to memorize the specifics
Many phlebotomy students find it challenging to remember all of the stopper colors, the additives and the types of blood tests. There are numerous helps on the internet and elsewhere, including flash cards you may download or make yourself. Online you'll also find charts, videos and even an online song to help you keep the short order basics straight.
Other innovative folks sell "order of draw" bracelets with beads matching the stopper colors, wristwatches with colored numbers in both short and long order styles, and handy "order of draw" badges you clip to your lanyard for a fast and easy reference. Your phlebotomy course instructors, like those at Western Career Training, are also a source for tips and tricks for memorizing the sequence.
Don't worry too much about how you will keep all of the colors and additives straight in your head. As you do more sticks, the order will become second nature to you. Then you will have achieved the rank of Master of the order.