Perform Blood
Collection for
Specialised Testing
HLTPAT411D
Specialised Testing
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The focus of this unit is the safe and accurate collection of specialised blood
collection and requires you to demonstrate knowledge of correct techniques
for venepuncture and skin puncture.
You need to understand the risks involved and the limit of your
responsibilities in specimen collection.
There is a lot more required than just getting the blood, you need to ensure
the correct tubes, method of collection, transport and ID of your client.
When you have completed this competency you should be able to:
Perform collection for specialised test
Perform post blood collection procedures
Label and store specimens for transportation
ID precise nature and requirements of the test request
Ensure compliance with pre test criteria
Select and prepare equipment and disposables and correct collection
containers for the Specialised test
Special Procedures
Some tests require special or additional collection procedures or are performed
on other body substances.
Collecting specimens for these tests may require special preparation,
equipment, handling or timing.
• Blood bank
• Blood cultures
• Coagulation specimens
• 2 hour post prandial glucose
• Glucose tolerance test
• Drug screening
• Cardiac troponin T and I
• Glycosated Hb
• Synacthen test
• Chilled specimens
Request forms
• The request form is a legal requirement
• Requested by the Doctor or healthcare
professional
• Becomes part of the client’s record
• Requires specific information that then
ensures the correct patient, orders are
followed, results are returned to the Doctor
and client is correctly billed
Request forms
• Barcodes are used to ID the specimen,
client and specimens
• Some forms have barcodes attached
• Allows for fast, accurate processing and
few mistakes
• Ensures that the specimens are tracable
Request forms
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At least 2 identifiers must be present
Date and time of collection
Collector’s ID
Tubes must not be labelled before
collection
Centrifugation
• All specimens should be transported to lab asap
• Routine specimens should arrive within 45 mins
and be centrifuged within 60 mins of collection
• Chemistry specimens should “sit” for at least 30
mins before centrifuging to allow for clotting
• Is the process where, after clotting, specimen is
placed in a centrifuge which spins blood at high
speeds. This creates a force that separates the
cells and plasma or serum
• Page 7
Haemolysis
• The bursting of RBC
• Haemoglobin leaks into the plasma and
blood results are compromised
• Specimen will be rejected by the lab and
patient will need to be redrawn
• Serum or plasma will have pink tinge
Haemolysis
Causes
• Poor selection of site
• Poor site preparation
• Extended tourniquet time
• Poor technique
• Vigorous tube mixing
• Transportation errors
Cholesterol testing
• Tests for lipids in the blood, HDL, LDL,
Triglycerides
• Blood composition is altered by ingestion
of food and drink
• Results will vary for at least 10 hours and
up to 12 hours after ingestion of food
• Water is encouraged in small sips
GTT
• Test used to diagnose glucose problems
• Monitors patient’s ability to metabolise glucose
by giving them a high dose of glucose without
adverse effects
• Issues that the patient may experience are hyper
and hypoglycaemia
• Insulin produced by the pancreas regulates
glucose levels
• GTT measures insulin response to a measured
dose of glucose by testing blood at certain times
GTT
• Sometimes insulin levels will also be
requested
• For gestational diabetes a 1 hour test is
usually ordered with 50g glucose
• The standard dose is 75g glucose
• Patient should fast for at least 12 hours,
but not more than 16 hours, water is
encouraged
GTT
• Normal, unrestricted diet for at least 3 days prior to test
• No acute illness for 2 weeks prior to test
• No recent illness and no smoking for 2 hours before the
test
• Fast for 8-10 hours prior to test, sips of water if thirsty
• Maintain normal activity prior to test
• Note medications on form
• Question Patient regarding allergies prior to test
GTT
• Remain fasting and at rest during the test, remain at collection
centre
• Advise Patient if they feel unwell during test to advise collection staff
• Blood or urine must be tested prior to drinking glucose to avoid
possible hyperglycaemic episode
• Collect first blood and label as fasting
• Give glucose, this must be complete within 5 minutes
• As soon as finished press timer for 60 minutes
• Blood is taken hourly timed from when the glucose drink has
finished
• If vomiting occurs, abandon test
Two Hour Post Prandial Glucose
• Post prandial means after a meal
• Glucose levels 2hours after a meal are
rarely elevated normally, but will be
increased in a patient with diabetes
• Due to this it is an excellent screening test
for diabetes
• Can also be used to monitor insulin
therapy
Glycosated Haemoglobin
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HBA1C
Monitors diabetes
Purple top( EDTA)
Performed usually every 3 months
Warmed and Chilled specimens
• Some components are broken down in the
presence of light
• This causes falsely decreased values
• Most common is bilirubin
• Others may be vitamin C, B12, B2, B6,
carotene, red cell folate, urine porphyrins
• Wrap in foil or use specific containers
Warmed and Chilled specimens
• An analyte is any component of blood
• Chilling slows down some metabolic processes
that will continue after specimen collection
• These specimens should be immersed in a
slurry of ice
• Examples are blood gases, ammonia, lactic
acid, plasma renin activity, glucagon
• Some specimens should not be chilled, so if
collecting with a chilled specimen, 2 tubes must
be collected
Warmed and Chilled specimens
• Some specimens should be kept warm
• They will clump if allowed to cool below
body temperature
• Need to be collected in pre warmed tubes
to 37 degrees centigrade
• Examples are: cryoglobulins, cold
agglutinins and cryofibrinogen
Keep at 37 degrees
Chill on ice
Protect from light
Cold agglutinin
Adrenocorticotropic
hormone (ACTH)
bilirubin
cryofibrinogen
Acetone
carotene
cryoglobulins
Angiotensin-converting
enzyme (ACE)
Red cell folate
Ammonia
Serum folate
catecholamines
Vitamin B2,B6,B12,C
Free fatty acids
Urine porphrins
gastrin
Urine porphobilinogen
glucagon
homocysteine
Lactic acid
Parathyroid hormone (PTH)
Cortisol
• This is a hormone released in times of
stress
• Levels are higher as the day goes on, due
to this blood should be taken between
0800 and 1000 or 1500 and 1700
• Time should be noted on request form
• Consider what you might do if the Patient
comes in at 1100 for their test??
Micro collection
• Blood for testing can be obtained by
puncturing the skin in the dermal layer with
a lancet
• Useful in children where removal of large
amounts of blood can lead to cardiac
arrest and anaemia
• General guide is babies under 2 years of
age should have a heel stick
Micro collection
• When collecting for a blood tube, depth is
more important than width
• Depth should be no more than 2mm
• Micro containers are small plastic tubes to
hold small amounts of blood
• They are colour coded just as vacutainer
tubes
Micro collection
• Capillary blood is a mixture of arterial,
venous and interstitial fluid
• Due to this, reference ranges will differ
• Potassium cannot be collected by this
method, as results will always be
inaccurate
Micro collection
When??
• Small amounts of blood are required
• No accessible veins
• Unsuitable veins
• POCT
• Babies where antecubital fossa is
unsuitable
Micro collection
Some tests cannot be done on capillary
blood
– ESR
– Most coagulation studies
– Blood cultures
– Potassium levels
Micro collection
• Warming the site before collection is
important
• This increases the blood flow up to 7 times
• Makes it easier to collect
Micro collection
• Clean the site with an alcohol wipe
• Air dry
• If it is still when the puncture is made it
can sting and the alcohol will interfere with
the test results
Micro collection
• Wear gloves and use an aseptic technique
• Puncture across the fingerprints and hold
downwards to ensure a rounded drop
• Blood can be squeezed out, however
milking will cause haemolysis
Micro collection
Synacthen
• This test is useful in diagnosing Addison’s Disease, which is a
disease of the adrenal glands
• Needs to be performed in a controlled environment with resus equip
available
• Should be performed between 0600 and 0900
• Fasting not required
• Any patients with allergies or asthma should not have the test
• First blood should be marked “baseline”
• Patient is then injected with 0.25mg Synacthen into deltoid and time
is noted on form
• Collect next two samples at 30 and 60 mins after synacthen and
label accordingly
Urea Breath Test
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Aids in diagnosis of infection with helico bacter pylori
Major cause of peptic ulcer disease
Non invasive
Either uses C13 or C14
Patient is asked to drink water in which tablet has been
dissolved
• If bacterium is present, the material will be broken down
into radio-labelled CO2 gas
• By testing expelled air the lab can determine presence of
organism
Urea Breath Test
• Timed test as there is a specific time that
the duodenum releases substance into
blood
• It then travels to the alveoli and is
transferred as CO2 in the breath
• Results is a definitive positive or negative
Blood Cultures
• Ordered when patient has fever of unknown origin
• Helps determine that micro organism is there and what
type they are
• Can be ordered immediately before or after a fever spike
• Collected in special bottles containing a growth medium
• One is aerobic and one is anaerobic
• Always first in order of draw
• Skin asepsis is vital to correct results
Blood Cultures
Blood Cultures
• Clean site with alcohol impregnated swab
and allow to dry
• Do not retouch the site
• Remove caps from bottles and swab tops
with alcohol
• Collect blood via the vacuette system
directly into bottles
• Mix well
Group and Cross Match
• When it is anticipated that a transfusion
will be needed, a blood test will need to be
performed to match the patient's blood to a
donor unit
• This is a critical test, where there is no
room for error
• Strict ID must be adhered to and all work
must be double checked
Group and Cross Match
• Dedicated 6ml EDTA (pink) tube must be useddo not share
• Collectors declaration form must be completed,
signed by the person collecting the sample
• Signature on blood tube must match signature
on request form
• Form details and patient samples must match.
Do not use abbreviations or variations of
patient’s name
Coagulation Specimens
• Must be filled until vacuum is spent to
obtain a 9:1 ratio of blood to sodium citrate
• Never pour partially filled tubes into each
other
• Transport on ice for some specimens
Drug Screening
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Random screening may occur
Can be done for up to 30 different drugs
Usually on urine
May need to be supervised
Will be sealed in specific container to
avoid tampering
Cardiac Troponin T and I
• Proteins specific to heart muscle
• Rise within 4 hours of a MI and may stay
elevated for up to 14 days
• Useful in diagnosis of MI
Client preparation
Therapeutic drug monitoring
• Some pharmaceuticals have patterns of
admin, body distribution, metabolism, and
elimination
• This can be measured in the blood
• Many drugs will have peak and trough
levels that vary according to dosage levels
and intervals
Client preparation
Posture
• Where position is changed
• Can vary lab results of some analytes
• Some larger molecules can not pass into
the tissues and are therefore concentrated
in the blood
• Examples are: enzymes, proteins, lipids,
iron and calcium
Client preparation
IV lines
• Blood should not be drawn above an IV
line
• Use opposite limb if possible
• Failing that draw below the line
• If unavoidable, medical staff to turn off the
infusion for 2 mins prior to collection, but
ensure that it has restarted after collection
and note on form
Clinical Risks
Anxiety
• Some patients will become anxious when
having a blood test
• How would you know this?
• What strategies can you use to help in this
situation?