Directorate of Laboratory Medicine1 Sample handling Malcolm Dunlop Directorate Quality Manager.

Directorate of Laboratory Medicine 1

Sample handling

Malcolm DunlopDirectorate Quality Manager


Clinical Sciences Building 1


Clinical Sciences Building 2


Laboratory Departments

Typical DGH

• Clinical Biochemistry (Chemical Pathology)

• Haematology

• Histopathology

• Microbiology


Laboratory Departments

Teaching hospital / tertiary referral• Clinical Biochemistry (Chemical Pathology)

• Haematology

• Histopathology

• Microbiology

• Immunology

• Virology

• Sub Fertility – associate department

• Cytology

• Others e.g. Genetics


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

• blood • urine & other fluids• faeces • sweat • semen• tissue


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


Phases of analysis• Pre-analytical (from the patient to the

lab)

• Analytical

• Post-analytical (from the lab to the notes)


From the patient to the lab• 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


From the patient to the labWhat can (does) go wrong?

• Incorrect container(s)

• Under-filling

• Mislabelling/ no labelling

• Incorrect storage/ transport (ice, warm, delay)

• Loss, breakage etc.


The Patient• Do patients always disclose history?

• Confused

• Frightened

• In pain

• Want to help !!!

• Are previous diagnoses available?


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


Requesting• Requested on PAS = electronic return

• Requested manually = NO electronic return

• Electronic/ manual mixed requesting = break in electronic record


Results• Telephoned results are the most

unsafe method

• Electronic are safest and quickest

• Hardcopy reports must be filed as per instructions


Blood collection• Ask patients to identify themselves

• When blood taken write all relevant details on collection tubes immediately


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


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


Other information• SHOULD include

– Ward– Date of collection– Time of collection e.g. Cortisol


Sample acceptance• Request form MUST contain

patient’s:-

– Surname– Forename– Date of Birth and/ or Hospital or NHS

number– Ward or clinic– Tests requested


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


Venous blood sampling

Syringe Hybrid Evacuated


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


Sampling problems - blood• Inappropriate site – drip arm,

mastectomy, burns etc

• Timing

• Incorrect use of tourniquet

• Wrong container

• Incorrect order of draw

• Transportation


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


Urine samples• Incorrect timing

• Inappropriate for test required

• Sterility

• Volume


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

Directorate of Laboratory Medicine1 Sample handling Malcolm Dunlop Directorate Quality Manager.

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