Sample handling
Malcolm Dunlop
Directorate Quality Manager
Directorate of Laboratory Medicine
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Clinical Sciences Building 1
Directorate of Laboratory Medicine
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Clinical Sciences Building 2
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Laboratory Departments
Typical DGH
• Clinical Biochemistry (Chemical
Pathology)
• Haematology
• Histopathology
• Microbiology
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Laboratory Departments
Teaching hospital / tertiary referral
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Clinical Biochemistry (Chemical Pathology)
Haematology
Histopathology
Microbiology
Immunology
Virology
Sub Fertility – associate department
Cytology
Others e.g. Genetics
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What constitutes a sample
• Any biological material taken from a
patient for diagnostic, prognostic or
therapeutic monitoring
• Under the new Human Tissues Act
tissue includes
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blood
urine & other fluids
faeces
sweat
semen
tissue
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Infection risks
• All samples must be considered to be
infectious
• Use of “Universal Precautions”
handling
• Never assume any sample is “safe”
• Today’s symptoms may be
tomorrow’s diagnosis of infection
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Phases of analysis
• Pre-analytical (from the patient to the
lab)
• Analytical
• Post-analytical (from the lab to the
notes)
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From the patient to the lab
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• What can (and does) go wrong
Incorrect identification of patient
Patient preparation – fasting, diet,
supine, time, drugs.
Sample poorly/ incorrectly taken
Inaccurate timing
Wrong type of sample
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From the patient to the lab
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What can (does) go wrong?
Incorrect container(s)
Under-filling
Mislabelling/ no labelling
Incorrect storage/ transport (ice,
warm, delay)
Loss, breakage etc.
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The Patient
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Do patients always disclose history?
Confused
Frightened
In pain
Want to help !!!
Are previous diagnoses available?
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Quality
• Laboratories can only produce
quality results on quality samples
• And on quality requests
• Rubbish In Rubbish Out
• Ideal sample mimics the in vivo state
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Requesting
• Requested on PAS = electronic return
• Requested manually = NO electronic
return
• Electronic/ manual mixed requesting
= break in electronic record
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Results
• Telephoned results are the most
unsafe method
• Electronic are safest and quickest
• Hardcopy reports must be filed as per
instructions
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Blood collection
• Ask patients to identify themselves
• When blood taken write all relevant
details on collection tubes
immediately
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Sample acceptance
• Patient safety is of the utmost
importance
• Samples and requests MUST allow
clear identification the patient
• Samples identified incorrectly will
NOT be processed
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Sample acceptance
• The sample MUST include patient’s:– Surname
– Forename
– Date of Birth or Hospital Number or NHS
number
– Histology specimens MUST include
Hospital number
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Other information
• SHOULD include
– Ward
– Date of collection
– Time of collection e.g. Cortisol
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Sample acceptance
• Request form MUST contain
patient’s:– Surname
– Forename
– Date of Birth and/ or Hospital or NHS
number
– Ward or clinic
– Tests requested
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Samples for Blood Transfusion
• MANDATORY identification
requirements
– As previous plus signature and printed
name of requestor on form
– Signature of person collecting the blood
on the sample tube(s) and on request
form
– Date of request and of sample
• See Blood Transfusion Policy
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Venous blood sampling
Syringe
Hybrid
Directorate of Laboratory Medicine
Evacuated
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Blood collection
• Use the blood collection system in
use
• Advantages over needle & syringe
– Higher quality sample
– Minimises clotting mechanism
– Produces correct blood to anticoagulant
ratio when properly filled
– Easier
– Quicker
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Sampling problems - blood
• Inappropriate site – drip arm,
mastectomy, burns etc
• Timing
• Incorrect use of tourniquet
• Wrong container
• Incorrect order of draw
• Transportation
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Urine collection
• 24 hour sample must include all urine
passed in this period
• If less than 24h, inform the lab
• Mid stream sample – self explanatory
• Early morning sample – often best
• Correct container type
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Urine samples
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Incorrect timing
Inappropriate for test required
Sterility
Volume
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Other considerations
• Swabs for culture may need specific
transport media e.g. Chlamydia
• Blood cultures – special bottles &
technique for taking the blood
• Tissue for Histology – fixative *
 Extreme care needed when using
formalin
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