Directorate of Laboratory Medicine
Factors Affecting the Results or Processing of Haematology Tests
Test
All Tests
Factor Affecting
Outcome
Result/Processing
ALL SECTIONS OF HAEMATOLOGY
· Failed Specimen
· Would not process
Acceptance Policy
(Routine samples
and Blood
Transfusion
samples)
· Unlabelled
· Would not process
· Wrong sample for
requested test
· Would not process
· Wrongly labelled
· Would not process
· Sample leaked in
transit
· Would not process
(If multiple samples were put in the specimen bag ALL
samples would not be processed)
· Sample broke in
transit
· Would not process
(If multiple samples were put in the specimen bag ALL
samples would not be processed)
COAGULATION
· Would not process
Routine
clotting
tests
Routine
clotting
tests
Under filled
sample
Routine
clotting
tests
Lipaemia
All clotting
tests
Clotting
assays
Haemolysis
Clotted
Secondary
clot in frozen
sample
DLM User Guide 2008
· Would process
Depending on the degree of haemolysis an estimated result
may be reported off the analyser with a comment ‘? Validity of
result due to haemolysis’
· Would process
Depending on the degree of lipaemia an estimated result may
be reported off the analyser with a comment ‘? Validity of
result due to lipaemia’
· Would not process
· Depending on size of clot would process and
add comment ‘? Validity due to secondary
clot’ or would not process and add comment
‘Clotted’
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Directorate of Laboratory Medicine
FBC
Small sample
FBC
&
ESR
FBC
&
Film
FBC, ESR
&
Retic
FBC
Small sample
CSF
Bone
marrow
smears
X-Match
Samples
&
Grouping
Samples
Grouping
Sample
Samples for
Cold
Agglutinins
Red Cell
Folate
Red Cell
Folate
Ferritin ,
B12, Serum
folate
Haematinic
assays
Haemolytic
assays
Plasma
Viscosity
Old Sample
(Greater than 48
hours)
Clotted Sample
EDTA may cause
clumping of platelets
Contaminated with
red cells
Not enough marrow
material to perform
stains on
Extreme Haemolysis
Clotted Sample
BLOOD COUNTS
· Paediatric- would process if there is greater that 200ulotherwise comment ‘Insufficient’
· Adult – would process if blood volume is sufficient to reach the
bottom of the label- otherwise comment’ Insufficient’
As above PLUS,
· If volume is less than 2 ml only FBC will be performed.
· ESR will be reported as ‘Insufficient’
· FBC would not be processed and comment-‘Too old for
analysis’
· Film would be reported as –‘Too old for morphology’
· Would not be processed
· This phenomenon would result in seemingly low platelet countlaboratory will ask for citrated (Coag) sample to get an
accurate measurement of the platelets
· Would process-appropriate comment will be added
· Could not perform stains-repeats would be requested
BLOOD TRANSFUSION
· Would not use- repeats will be requested
· Would not process
Sent to the lab ‘cold’
· Would not process
i.e. not in warm
water
HAEMATINICS and HAEMOLYTICS
No EDTA sample
· Only serum folate can be measured
Sent- only clotted
sample
EDTA clotted
· Would not process
Only EDTA sent
Haemolysis
· Would not process
· Would process and add appropriate comment
EDTA clotted
· Would not process
Sample stored in
fridge
· Would not process
This list is not exhaustive-there may be other factors affecting the reporting of results
which are not listed
DLM User Guide 2008
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