Leeuwenhoek had stolen and peeped into the fantastic sub-visible world of little things, creatures that had lived, had bred, had battled, had died, completely hidden from and unknown to all men from the beginning of time. Beasts these were of a kind that ravaged and annihilated whole races of men ten million times larger than they were themselves. Beings these were, more terrible than fire-spitting dragons or hydra-headed monsters. They were silent assassins that murdered babies in warm cradles and kings in sheltered places. It was this invisible, insignificant, but implacable-and sometimes friendly- world Leeuwenhoek had looked into for the first time of all men of all countries. ~Microbe Hunters

Wednesday, 17 April 2013

Order of Draw

In phlebotomy, or the practice of drawing blood on a patient, there is a certain order in which phlebotomists must fill the tubes required for testing. There are different additives in each tube, and there is a small, very small, chance that there will be cross-contamination of the tubes. The order of the tubes goes from most sterile or lease selective, to most selective. The order of draw goes as follows:
·         Yellow top tube: goes to microbiology (usually for testing of bacteria in the blood)
·         Blue top tube: contains sodium citrate as anticlotting agent
·         Red top tube: serum tube (clots blood so Lab can work with the serum)
·         Green top tube: contains heparin as an anticlotting agent
·         Purple top tube: contains EDTA as anticoagulant and goes to hematology
·         Grey top tube: fluoride tube for glucose testing
Sort of boring. If you need to get your blood taken, I have a few questions that you can ask your Lab professional. I found a little paper in my backpack randomly, and I will copy the questions onto here:
·         How is the test done?
·         How accurate is the test?
·         Will the test be uncomfortable?
·         What do I need to do to prepare for the test?
·         Can I drink before the test? What and how long prior?
·         Can I smoke before the test?
·         Can I eat before the test?
·         Can I exercise before the test?
·         Where will the test be done?
·         What time is best for collection?
·         How long does the test take?
·         How will I feel during the test?
·         Where do I have to go for the sample collection?
·         How long will the collection of sample take?
·         When will the results be sent to my doctor?
Some tests that are run on your blood sample are dependent on consistency. For example, if you are getting your blood tested for cholesterol and lipids, it is probably not an okay thing to eat 2 bacon and cheese sandwiches before the test. It would instantly increase your blood lipid volume. Also, if your doctor is ordering a test on muscle damage or finding out if you had a heart attack, it is probably not a good idea to exercise before the test. Or glucose levels, probably wasn’t wise to eat the bag of candy.

It is not always just “common sense” when it comes to what you can and cannot do before a blood test, because things happen at the molecular level, and I guarantee that you do not know your body as well as the Laboratory professionals running the tests will know. We are intelligent people. There is very few ways to trick us. For example, you tried to starve yourself and cut out sugar like crazy before getting tested for “diabetes”? We will see that, sure your current glucose level is low, but wait, your glycated hemoglobin is high? They tried to trick us! But guess what, we caught you. It is always a good idea to ask your health professional for advice on what to do for lab tests. If would really suck if we had to ask you to come in again for a re-draw because you were “being funny” the first time. 

Darn good and sure of it,



  1. Very informative! Thanks for sharing!

    1. My pleasure! Thanks for stopping by!

  2. That is so cool you can detect the tricks.

    1. It really makes me fell like a spy...muahaha

  3. Very interesting. Thank you for sharing. I didn't know this. New follower here. I'm stopping by from the "A to Z" challenge and I look forward to visiting again.


  4. That's a very helpful list of questions to ask the lab professional, and it's also good to know that there's no point in trying to fool the tests with some last-minute dietary adjustments. Apparently, if we want good results, we're going to have to sustain those tactics for a lot longer!

    1. That's true! If you want to fool them with your intake of sugar, it's gonna have to be about 3 months!! It's not like the dentist where you can floss a few days before and fool them that you do it all the time!

  5. I'd not have thought of asking all those things, very interesting. I've need tests often in the past and no one has ever said anything except for the not eating for x number of hours for some tests. I'll certainly ask more in future, thanks.
    maggie at expat brazil

    1. Not eating is a big one, and normally people comply with that one.
      Thanks for stopping by!