An informative document about blood collection tubes

1. PHLEBOTOMY
Phlebotomy is the practice of drawing blood from patients and taking the blood specimens to
the laboratory to prepare for testing and researches.
Types of Tubes
THE PURPLE ONE (aka “Lavender”)
These bottles are generally used for haematology tests where whole
blood is required for analysis.
This tube contains EDTA(ethylenediaminetetraacetic acid), which acts as a
potent anticoagulant by binding to calcium in the blood.
COMMONTESTS:
o full blood count (FBC)
o erythrocyte sedimentation rate (ESR)
o blood film for abnormal cells or malaria parasites
o reticulocytes
o red cell folate
o Monospot test for EBV
o HbA1C for diabetic control
o parathyroid hormone (PTH)

2. THE PINK ONE
The pink bottles work in the same way as the purple ones, but are
specificallyused only for whole blood samples being sent to
the transfusion lab.
This tube also contains the anticoagulant EDTA.
COMMONTESTS:
o group and save (G&S)
o crossmatch (XM)
o directCoomb’s test (aka directantiglobulin test) for autoimmune
haemolytic anaemia

3. THE BLUE ONE
The blue bottle is used for haematology tests involving
the clotting system, which require inactivated whole blood for
analysis.This contains buffered sodium citrate, which acts as
a reversible anticoagulant by binding to calcium ions in the blood and
subsequently disrupting the clotting cascade
COMMONTESTS:
o coagulation screen including bleeding time for platelet
function, prothrombin time (PT) for extrinsic pathway, activated partial
thromboplastin time (APTT) for intrinsic pathway, and thrombin time
(TT) or fibrinogen assay for the final common pathway
o D-dimer for thrombosis e.g. due to DVT or PE
o INR for monitoring patients on warfarin (this is calculated from the
prothrombin time
o activated partial thromboplastin ratio (APTR) for monitoring patients
on IV heparin infusions (this is calculated from the APTT)
o anti-Xa assay for monitoring patients on high-dose low molecular weight
heparins like tinzaparin

4. THE YELLOW ONE (aka “Gold”)
These bottles are used for a huge variety of tests requiring
separated serum for analysis, including biochemistry, endocrinology,
oncology, toxicology, microbiology and immunology.
This tube is known in the lab as the SST (serum separating tube). It
contains two agents; silica particles and a serum separating gel. The silica
particles work to activate clotting and cause the blood cells to clump
together.
COMMONTESTS:
o biochemistry tests are the ones you will encounter most commonly:
o urea and electrolytes (U+E) – this includes urea, creatinine, sodium
and potassium
o C-reactive protein (CRP)
o liver function tests (LFTs) – this includes bilirubin, ALP, AST/ALT,
GGT, total protein and albumin
o amylase assay
o bone profile – this includes calcium, phosphate, ALP and albumin

5. o magnesium assay
o iron studies – this includes serum iron, ferritin, transferrin saturation and
total iron binding capacity
o lipid profile – this includes cholesterol, LDL, HDL and triglycerides
o thyroid function tests (TFTs) – this includes TSH, free T4 +/- free T3
o vitamins e.g. vitamin B12
o troponins – this requires 2 samples to be taken at different times to
assess the acute trend
o creatine kinase (CK)
o urate
o serum osmolality – this requires a urine sample to be taken at the same
time
o endocrinology: beta-hCG, calcitonin*, cortisol, EPO, sex hormones,
growth hormone, IGF-1
o tumour markers: PSA, CEA, CA-125, CA19-9, AFP, lactate
dehydrogenase (LDH)
o toxicology: ethanol, cannabis, opiates, benzodiazepines, other drugs
e.g. cocaine, amphetamines
o drug levels: paracetamol, salicylates (aspirin), digoxin, lithium,
gentamicin, carbamazepine
o microbiology/virology: serologyfor a wide variety of bacterial, viral, fungal
and parasitic infections including HIV and viral hepatitis
o immunology: immunoglobulins, complement, autoantibody screen,
rheumatoid factor, thyroid antibodies, α1AT, ACE

6. THE GREY ONE
The grey bottle is only used fo two tests,so compared to the yellow one it’s
fairly easy to remember! It is used for biochemistry tests requiring whole
blood for analysis.
This contains two main agents. Sodium fluoride acts as an antiglycolytic
agent to ensure that no further glucose breakdown occurs within the
sample after it is taken. Potassium oxalate acts as an anticoagulant.
COMMONTESTS:
o glucose – this can be fasting or non-fasting, or part of a glucose
tolerance test (GTT)
o lactate

7. THE RED ONE
The red bottle is less common – it is used for biochemistry tests
requiring serum which might be adversely affected by the separator gel
used in the yellow bottle.
This contains silica particles which act as clot activators.
COMMONTESTS:
o the use of this bottle varies greatly – some hospitals use it for many
sensitive tests, including hormones, toxicology, drug levels,
bacterial and viral serology and antibodies, whereas others seem to
only use it for a few very specific purposes and use the yellow bottle for
most things.
o my hospital definitely uses it for ionised calcium, but not much else
THE DARK GREEN ONE
This less commonly used bottle is for biochemistry tests which
require heparinised plasma or whole blood for analysis.
This contains sodium heparin, which acts as an anticoagulant.
COMMONTESTS:
o ammonia*
o insulin*
o renin and aldosterone

8. THE LIGHT GREEN ONE
This rare species of bottle is used for biochemistry tests
requiring separated heparinised plasma. I have never actually used one
but have seen them on the dermatology ward.
This bottle is known as the plasma separator tube (PST). It
contains lithium heparin, which acts as an anticoagulant, and a plasma
separator gel similar to that used in the yellow bottle, which acts to
separate out the plasma layer.
COMMON TESTS: it can be used for routine biochemistry, but most
hospitals seem to use the yellow bottle for this. It can also be used for
blood ethanol provided the sample is not for legal purposes.
OTHER ONES
o white – used for molecular diagnostics such as PCR and DNA
amplification studies
o black – for paediatric ESR

9. Prepare by:
Zubair Rahman
3RD
batch MLT IPMS KMU
Peshawar.