When the doctor/nurse takes blood from you, why do they try to find a vein, not an artery? And also why is this mainly done on the arm as opposed to other parts of the body?
In: Biology
First post here. I’ve been a phlebotomist for 16 years and specifically on pediatrics for the last 13.
A lot of people have already mentioned the pain factor but you also want to think about the sample type and the test results you get from each. Veins have venous blood, arteries have arterial blood and capillaries give capillary blood.
Venous blood is on its way back to the heart, so you get your base line results there. Your body has already soaked up all of the oxygen the red blood cells are carrying. Thats why its dark. Arterial blood is bright red of course because its pumped straight from your heart with all the oxygen. Your capillaries return your blood to your veins so its also a bright red. Venous blood is the primary sample type to run the majority of tests.
Capillary blood is used for quick tests like jaundice tests in babies or sugar tests for diabetics. I typically stop poking babies heels at around 4 to 5 months because the capillaries are to deep to reach. Then you end up squeezing the foot to hard and then hemolizing the sample. Thats bad. You’ll end up having to recollect the sample.
Arterial blood as mentioned before is used to measure your oxygen level mostly. Usually when you’ve had a heart attack and not pleasant at all.
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