Healthcare and Medicine Reference
In-Depth Information
Table 5.1 A summary of blood collection bottles (adapted from www.
vacuette.com).
Bottle
lid colour
Tube contents
Tests
Purple
EDTA
(ethylenediamine-
tetraacetic acid)
Full blood count, ESR, malaria
screen, tacrolimus, cyclosporin,
HbA1c, PCR analysis, cross-match
and group and save
Gold
Clotting accelerator and
separation gel
Biochemistry testing, tumour
markers, endocrine testing
Light blue
Trisodium citrate
Coagulation testing
Red
Clotting accelerator
Serology, vancomycin, immunology,
insulin, B12, folate
Grey
Sodium fl uoride/
potassium oxalate
Glucose
Figure 5.2 Equipment for phlebotomy.
Green
Lithium heparin
Ammonia
Royal blue
Sodium heparin
Trace elements
vein combines with the cephalic vein (located medially in the
antecubital fossa.) and is often used for venepuncture.
Figure 5.3 A multisampling needle and collecting tube.
Collection
There are different types of collection bottle depending on the
test being performed. As a rule of thumb, anything for haemato-
logical investigation, group and save or DNA analysis such as PCR
amplifi cation requires blood collection in an EDTA (ethylenedi-
aminetetraacetic acid) collection tube. This tube usually has a purple
lid. Biochemical investigations are collected in tubes containing a
clotting accelerator and separation gel. These are usually gold or yel-
low. Clotting investigations require trisodium citrate tubes which
are usually light blue in colour. Table 5.1 is a guide for blood bottles
in the UK. Check local guidelines for further information.
Samples should be delivered to the laboratory as soon as taken
and always the same day.
Figure 5.4 A butterfl y needle.
Equipment: methods for blood collection
There are several means by which a phlebotomist may obtain blood
The pros and cons of each can be found in Box 5.1.
Vacutainer™ system
One of the safest means of phlebotomy involves the use of a
Vacutainer™ system. This consists of a cylindrical clear plastic
collecting device, known as a tube holder, which is attached to either
a multisampling needle (Figure 5.3) or a butterfl y needle and luer
adaptor (Figure 5.4). Vacutainer™ blood bottles are loaded onto the
luer adaptor within the tube holder; the vacuum present causes blood
to fl ow directly from the vein and into the bottle (Figure 5.5).
Box 5.1 Pros and cons of the different equipment used in
phlebotomy
Pros
A Vacutainer™ system is safest.
A needle and syringe or use of a butterfl y demonstrates a
fl ashback to confi rm the needle has entered the vein.
Needle and syringe
This is the traditional method for phlebotomy. It is simply a needle
(normally 21G - green) attached to a syringe.
Cons
A multipurpose needle with a tube holder does not allow for a
fl ashback. Therefore, until a Vacutainer™ tube is loaded onto
the tube holder it is unclear if the vein has been successfully
punctured.
When using a Vacutainer™ system, the loading of different blood
Step-by-step guide: venepuncture
Give a full explanation to the patient in simple terms and
ensure they consent to the procedure. Prepare equipment
(Figure 5.2)
collection tubes whilst keeping the needle still within the vein
requires some dexterity and practice.
 
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