In this post, I am going to write about a tutorial given by one of our colleague. All of us have to attend this tutorials unless we are busy at our work stations. These tutorials are given at least once every 2 weeks.
Topic for today: blood collection
The Clinical and Laboratory Standards Institudes (previously known as NCCLS) sets guidelines of procedure to ensure that quality specimens are collected for laboratory testing. Upon collection, all plastic tubes must be gently inverted 5-10 times to provide thorough mixing of the additives. Also, it is important to note that shaking of blood tubes may cause hemolysis of the blood.
Order of draw of blood collection tubes procedure:
1st) Blood culture bottles
Culture bottles should always be drawn first. this is to reduce contamination of the blood specimen which might cause the analyzer to detect a positive bottle. thus, leading to a wrong treatment for the patient.
2nd) Citrate (light blue) tube
blood to be taken as soon as possible before formation of microclots. also, this tubes must be drawn before the collection of serum tubes (red and yellow) to prevent comtamination with clot activator which are present in them.
3rd) Serum (red/yellow) tube
4th) Heparin tube
5th) EDTA (purple) tube
they contain potassium hence, it is not advisable to collect blood into this tube before the serum tubes (chemistry tests). this is because serum tubes might be contaminated with potassium causing inaccurate results. for eg, K+ level will be falsely high and Ca+/Mg+ levels will be falsely low.
6th) Fluoride/Oxalate (grey) tube
oxalate pesent in this tube can be obstructive to cell membrane. thus, it is not advisable to collect blood into this tube before both serum tubes (chemistry tests) and EDTA tubes (haematology tests). if both tubes are contaminated with oxalate, it will also lead to inaccurate results.
wendy/0701158h
answers (there's some prob i couldnt post a comment)
1. nyzah,
heparin tube is the green top tube. most chemistry tests can be done using this tube. for eg, renal panel, lipid panel etc.
2. shemeema,
the citrated tube is used for running the coagulation panel (PTINR/aPTT). hence, the presence of clots will affect the result.
thanks,
wendy.
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hie wendy,
ReplyDeletewhat colour is the heparin tube?and what tests are usually done for blood collected in the heparin tube?thx :)
nyzah
0702888I
Hi Wendy,
ReplyDeleteYou mentioned that for the Citrate (light blue) tube, blood have to collected before the formation of microclots. How does the microclots affect the test that is to be done?
Shameema
Hey Wendy!
ReplyDeleteWhat type of blood culture bottles do you use?
Felicia
0703345I
Hi Wendy!
ReplyDeleteIs there any difference between the red and yellow serum tube?
Vanessa Chua
0702099C
hii sorry for the first 2 qns i had to reply in the post because i couldnt post a comment here.
ReplyDelete3) hi felicia,
in the micro lab, we use the aerobic and anaerobic culture vials. two kinds only.
4) hi vanessa,
the yellow top one contains gel but the red top on doesn't. the gel is used to separate the red cells from serum after spinning.
thks :)
hi wendy,
ReplyDeleteyou mentioned the Fluoride/Oxalate (grey) tube.
what are the purposes of collecting the blood in this type of tubes? and what does the additives (fluoride/oxalate) does to the blood?
jiahui
tg01 0703605f group 2
hi,
ReplyDeletethis grey tube is used for glucose determinations.
Glucose values in unpreserved blood decrease quickly after collection as glucose is metabolised by the blood cells. So the additives contained in this Fluoride/Oxalate tube will stop enzymatic activity at the glycolytic pathway.
thks.