Describes the mission of laboratory services, the phases of performing laboratory tests, factors affecting laboratory tests and strorage and transport of laboratory samples

1. Management of Health Laboratory
Services

2. Mission and Management of
Laboratory Services
Mission of Laboratory Services:
To provide high quality of services, in the right place and at
the right time in respect of the needs of:
- Patients
- Clinicians
- Epidemiologists
- Environmental Sanitarians
Management of Laboratory Services:
Is the guiding of human and physical resources (money,
equipment, reagents, materials and space) through the
laboratory towards determined goals and objectives,
achieving beneficial results for those served.

3. Phases of The Laboratory
Analytical Process
Phases Of The Laboratory Analytical Process
25 %
Analytical phase
Laboratory Technicians
18%
Post-Analytical phase
Reporting
Registration
Sending
20%
Pre-Analytical phase
outside laboratory
Nurses
Doctors
Patients
37%
Pre-Analytical phase
inside laboratory
Patients
Laboratory Technicians

4. Sources of Variations in
Laboratory Results
A- Pre-Analytical Sources:
 Preparation of the patient
 Obtaining the specimen
 Processing the specimen
 Specimen interference
 Storing the specimen

5. Sources of Variations in
Laboratory Results
B- Analytical Sources:
 Dispensing a sample aliquot into a reaction vessel.
 Combining the sample with one or more reagents.
 Recording some physical or chemical consequences of
the reaction.
 Calculating the value of the parameter measured.
C- Post-Analytical Sources:
 Accepting the result of the test by the Laboratory
Technician as being of good quality.
 Sending the report of the test to the requesting
physician.

6. Pre-Analytical Control
 The pre-analytical control includes control on the
following variations:
a. Biological sources of variation.
b. Variation due to specimen collection, transport and
storage.
 They are frequent sources of misinterpretation of
laboratory results, even when the laboratory
investigation has been satisfactorily performed.
 They may give rise to unnecessary discussions
between the laboratory and health care personnel and
may also lead to further unnecessary investigations.

7. Pre-Analytical Control
 It is therefore very important that collection of
specimens be done under standardized conditions,
which include:
a. The preparation of a patient prior to sampling
b. Recording of personal data, e.g. age, sex and clinical
diagnosis and treatment.

8. 1. Biological sources of
variation
The range of the reference values, as well as the results
obtained from measurements in a patient’s specimen are
affected by a number of pre-analytical influences, as
follows:
• Genetic
• Sex
• Age
• Nutrition
• Posture of the patient during specimen sampling.
• Physical activity.
• Non-periodic changes.

9. 1.1 Genetic Variation
 A number of genetically determined diseases are
endemic in certain populations. In these populations
the prevalence of the disease may be high,
 Some examples are:
- Sickle cell anaemia in African populations.
- Thalassaemia in Mediterranean and Asian
populations.
 Other genetic disorders are more or less equally
distributed in different populations.

10. 1.1 Genetic Variation
Examples are:
• Familial hypercholesterolaemia.
• Phenylketonuria.
• Cystinuria.
• Hypothyroidism.
 More than 300 variants of the haemoglobin molecule
have been identified, only a few of which cause
clinical symptoms

11. 1.2 Sex-related variation
 The differences of the reference ranges for some of the
analytes as observed in an adult population are given
below:
Test Male Female
ESR mm/h 1-13 1-20
Heamoglobin (g/dl) 13-18 12-16
Haematocrit (%) 40-54 39-51
Uric acid (µmol/L) 210-420 150-350
ALT (U/L) 10-50 10-35
AST (U/L) 10-50 10-35
 For the following analytes the sex-dependent differences in
concentration are negligible: urea, glucose, alkaline phosphatase.

12. 1.3 Age-dependent variation
 Age-dependent changes occur in a number of
haematological and chemical tests.
 Most impressive are the differences of results from
blood of a neonate when compared with the normal
ranges for adults, such as in the case of bilirubin,
glucose, total protein, and erythrocyte
sedimentation rate.
 Some analytes reach values which could be
misinterpreted as highly pathological if the age of the
patient is not taken into account.

13. 1.4 Nutrition-dependant
variant
 The nutritional status of the patient may sometimes
strongly affect the concentration of a number of
analytes in blood. It may even be necessary to keep
him/her on a special diet prior to the investigation of
blood, so as to obtain more accurate information
about metabolic status.
 Ingestion of large volumes of water may result in
falsely normal urine glucose concentration; on the
other hand dehydration may cause elevated urine
glucose concentration.
 In some subjects ethanol ingestion acutely changes
activities of ALT and AST.

14. 1.4 Nutrition-dependant
variant
 Smoking does not usually influence results of common
tests; however, Hb is increased in chronic smokers.
 Changes in some analytes due to nutritional state:
Analyte Change
Serum triglycerides Elevated after fat-rich meal
Serum urea Elevated after meat ingestion
Serum glucose Elevated after carbohydrate
ingestion
Aspartate aminotransferase
(AST)
Elevated after alcohol ingestion
Urine ketone bodies Increased during fasting
Urine pH Elevated after ingestion of
vegetables.

15. 1.5 Variation due to posture of the
patient during blood sampling
 The changes are more pronounced when blood is
taken from a healthy person changing position from
horizontal to upright, than changes resulting from
technical factors during investigation in a laboratory
with good practice.
 A change from the upright to the horizontal position
may result in a change in concentration or activity of
certain tests up to 15%.
 Changes in analytes of patients who changed from a
horizontal to an upright position:

16. 1.5 Variation due to posture of the
patient during blood sampling
Analyte Change
Urea -3%
Creatinine +5%
Protein +10%
AST +15%
ALT +15%
Alkaline Phosphatase +12%
Cholesterol +8%
Haematocrit +10%
Albumin +10%

17. 1.6 Variation due physical exercise
 Physical exercise may cause pronounced changes in the
activity of enzymes occurring in muscle.
 Creatine phosphokinase activity (CK) as well as
aspartate transaminase(AST) increase markedly after
physical exercise.
 Increases of Hb concentration and PCV and of the RBC,
WBC and platelets in dehydrated patients are due to
the decrease in plasma volume.
 There is an increase in the number of circulating
neutrophils during and following physical exercise.

18. 1.7 Variation due to non-periodic
changes
 The occurrence of a non-periodic change, such s
pregnancy, may alter the reference value for a number
of common analytes., such as transaminase activities,
serum lipids and hormones.
 There is usually and increase in the number of
neutrophils during pregnancy – sometimes, there is
even a neutrophilic leukocytosis.
 The ESR also increases during pregnancy.
 On the other hand, the Hb concentration, PCV and RBC
decrease, due at least partially to an increase in plasma
volume.
 The effect of interactions and/or interferences,
especially by drugs, on laboratory results has to be
remembered.

19. 2. Variation due to specimen collection,
transport and storage
 The most frequent source affecting laboratory analysis in
a well-functioning laboratory is not the laboratory
investigation itself but specimen preparation and errors in
identification or labeling.
 Changes in the composition of a specimen can be caused
during:
• Collection.
• Transportation.
• Centrifugation.
• Storage.

20. 2.1 Blood specimens
 2.1.1 Collection of blood specimens:
 The simplest technique for blood collection is
capillary puncture.
 Venous blood samples are preferable for
determination of platelet counts because platelets
adhere to the puncture wound.
 Preventing haematoma during vein-puncture:
- Use preferably veins in the elbow area, and only
major veins.
- Be careful that the bevel of the needle is fully
inside the vein.
- Be careful not to transverse the vein.

21. 2.1 Blood specimens
 Preventing haematoma during vein-puncture:
- Loosen the tourniquet and ensure haemostasis with a
dry sterile cotton ball before pulling out the needle.
 Blood samples should preferably not be taken from
intravenous lines but, if this is unavoidable, care must be
taken to ensure that the intravenous fluid does not dilute
the sample.
 If the blood has been collected in a syringe, the needle is
removed before the tube is filled.
 The syringe is placed below the rim of the tube and the
blood is expelled gently down the side.
 If the sample is to be anticoagulated, the blood is mixed
gently with anticoagulant by repeated inversion.

22. 2.1.2 Preservation of Blood
specimens
 The preferred anticoagulant for most haematological
investigations (e.g. of Hb concentration, PCV, WBC, RBC,
reticulocyte counts or platelet count) is a dry EDTA.
 The final concentration of anticoagulant should be 1.5 ( + 0.3)
mg/ml blood.
If the final concentration is more than 2mg/ml blood, this may
cause erroneously low PVC, it may also cause cellular artifacts
due to shrinkage of blood cells in films made from the blood
samples.
 For erythrocyte sedimentation rate (ESR) the ratio of blood to
citrate is 4:1 (v/v).
 Although heparin can be used for routine haematological
investigations, it is not recommended because cells deteriorate
more rapidly in heparinized than in EDTA-anticoagulated blood.

23. 2.1.3 Preparation of thin blood
film
 Making the spreaders: select a slide with perfectly
smooth edges and make a diagonal scratch across the
two corners at one end and snap off the two corners
with a pain of pliers.
 Disinfect the tip of the third or fourth finger with
ethanol. With the lancet prick the lateral side of the
ball, not too close to the nail bed.
 Bring the end of the slide into contact with a small
drop of blood, being careful not to let the slide come
into contact with the skin.
 Place the slide on a flat surface and steady it with the
index finger and the thumb.

24. 2.1.3 Preparation of thin blood
film
 Place the end of the spreader at an angle of 45” to the first
slide slanting towards the drop of blood. Draw the
spreader back until it touches the drop of blood and wait
until the blood has spread along the entire edge of the
spreader.
 With a firm fast motion push the spreader along the first
slide maintaining the 45” angle. In this way the blood is
drawn after the spreader in a thin smear which if the
original drop is small enough, ends in a drawn-out tail well
before reaching the end of the first slide.
 Wave the slide so it dries quickly, In humid seasons the
drying of the film can be speeded up by waving the slide 5
cm away from the flame of spirit lamp.
 With a lead pencil mark the thick part of the film with the
patient’s name or number.

25. 2.1.4 Common faults in
preparing thin blood films
Common faults in preparing thin blood films
Fault Cause
The end of the film is lost The drop of the blood is too
big
The film ends in a thick line The spreader has been lifted
up too early
The end of the film is ragged The edge of the spreader is
uneven
Lines along the film Blood is clotting when the film
is made
Lines across the film The spreader was pushed
forward jerkily
Holes in the film Greasy slide

26. 2.1.5 Transport and storage of
blood
 As a principal rule in laboratory investigation, whole
blood should not be stored.
 Blood, urine, other body fluids and excreta are excellent
media for the growth of contaminating bacteria
 If blood, plasma or serum cannot be directly
transported to the laboratory or immediately
investigated, they should be kept in the dark at 4 to 8
oC in a stoppered vial to prevent evaporation of water
and degradation of analytes by light.
 Analytes affected by prolonged storage of blood
specimen:
Creatinine, Glucose, Alkaline phosphatase, AST, Hb,
PCV, WBC, Reticulocytes, Platelets, ESR.

27. 2.1.5 Transport and storage of
blood
 Stability of analytes in serum stored in a stoppered
tube:
Analyte 4 oC 20-25 oC
Bilirubin measurement in fresh serum
Creatinine 24 d not recommended
Protein 6 d
Triglyceride 2 d not recommended
Urea 3 d 24 h
Uric acid 5 d 5 d
Alkaline phosphatase 7 d 7 d 10% decrease
AST 3 d 8% 3 d 10% decrease
ALT 3 d 10% 3 d 17% decrease

28. 2.1.6 Haemolysis
It is important to avoid haemolysis at every step during blood
sampling, transportation and storage.
Artificial causes of haemolysis:
 Blood sampling through a too small needle.
 Forced suction of blood in the syringe during blood
collection.
 Vigorous shaking of blood in the syringe or test tube.
 Forced expulsion of blood from the syringe, especially
through a needle.
 Centrifuging blood samples at high speed before
completion of clotting.
 Freezing and thawing of blood.
 Unclean tubes with residual detergent.

29. 2.1.6 Haemolysis
Artificial causes of haemolysis:
 Water (or hypotonic solutions) in syringe or tube.
Chemical tests affected by haemolysis:
 Bilirubin
 Cholesterol
 Alkaline phosphatase.

30. 2.1.7 Sources of analytical variation
after blood collection:
 Contamination (microbial or chemical)
 Prolonged transportation and storage prior to measurement due
to:
- glucose uptake by blood cells
- liberation of enzymes from blood cells
- liberation of ions from blood cells
- rapid decay of enzyme activity
 Temperature
 Incorrect specimen identification.
 Exposure to light: bilirubin.
 Transport in open or poorly stoppered vials or leaving specimens
uncapped on the bench. This leads to evaporation of water from
plasma, or conversely water uptake in a humid atmosphere.

31. 2.2 Urine specimen
 A random urine specimen collected in a clean, but not-
sterile container is used for qualitative or semi-quantitative
examination of contents such as glucose, protein, pH,
specific gravity, bile pigments, and possible presence of
blood, pus, or crystals.
 Often the first morning-voided specimen is requested
because it gives the urine concentration most accurately.
 Quantitative urine analysis is helpful for assessment of
kidney function.
 For chemical and microbiological examination the urine
must be collected “clean”, because any discharge or pus
from the vagina or external genitals added to the urine will
invalidate the examination.

32. 2.2 Urine specimen
 For the demonstration of eggs of schistosomes a random
urine sample should preferably be collected between 10
am and 2 pm, as the concentrations of eggs are greater
during this period. Particularly in the last drop of the
passed urine. Exercise prior to the collection will result in
an excretion of more eggs.

33. 2.2.1 Urine collection
 Give the patient a clean, preferably sterile container of
appropriate size (50 ml or more; for quantitative chemical
investigations the whole volume excreted during 24 hours must
be carefully collected in a 2-litre container).
 The container must be free of detergents, which may cause false
determinations.
 The container should be pre-lablelled with identification data, at
least the patient’s first name and surname.
 Instruct the patient before the collection, preferably with
illustrations. Tell him or her not to touch the inside or rim of the
container. Ensure that his/her hands are clean.
 Specific instructions should be given to each category of patients:
- Male patients - Female patients
- Patients not requiring assistance
- Bedridden patients requiring assistance - Infants

34. 2.2.2 Urine transportation
 Urine specimens should be transported to the laboratory
within one hour for chemical and microbiological
investigations, the reason being the growth of bacteria.
 A specimen containing 103
bacteria/ml after collection may
have 105
bacteria/ml 2 hours later when kept at ambient
temperature.
 If transport cannot be immediately assured, the specimen
should be refrigerated and processed within 24 hours.
Additives are not required.

35. 2.3 Sexually transmitted disease
specimens:
 Sexually transmitted diseases (STD) are caused by a large variety of
viruses, bacteria, fungi and parasites.
 With a few exceptions all these microorganisms are too delicate and
fastidious to grow in vitro. Culture of these organisms will also
detect a number of asymptomatic carriers, and is therefore not
recommended.
 Their identification depends therefore upon the collection of an
appropriate specimen and upon its transportation under optimal
conditions to the laboratory.
 All specimens should be collected before the administration of
antibiotics or the application of topical drugs.
 Vaginal fluid should be collected by a doctor using a speculum and a
cotton swab.
 The exudate is immediately mixed with a drop of saline on a slide,
covered with a cover slip, and examined under the dry x40 objective
for motile trichomonas, budding yeasts, or clue cells. Yeasts can be
easily visualized by adding a drop of 10% potassium hydroxide (KOH)
to the exudate.

36. 2.4 Stool specimens:
2.4.1 Collection of stool specimen:
 Faecal material should be collected directly in the
container.
 The specimen should not be contaminated with urine.
 Stool specimens must not be left exposed to the air in
containers without lids.
 Rectal swabs should only be taken if the patient is unable
to produce a stool specimen.
 The technician should inspect every stool specimen and
record the observations on the request form. Note the
consistency (watery, liquid, mushy or formed) and the
presence of blood, pus, mucus or adult parasitic worms.

37. 2.4 Stool specimens:
2.4.2 Collection of stool specimen:
 Specimens for bacteriological examination should be
transported to the laboratory and processed within a few
hours. In case of delay the specimen should be refrigerated. If
longer delays cannot be avoided a special transport medium
should be used.
 Stool for parasitological examination can be preserved for
several weeks by mixing the specimen with at least 3 volumes
of preservative fluid.
 A 10% formalin (3.4% formaldehyde) solution is
recommended.
 For the detection of motile forms of Entamoeba histolytica
and other protozoa, suspected stools should be examined
within one hour after defecation, without preliminary
refrigeration.

38. 2.4 Stool specimens:
2.4.2 Collection of stool specimen:
 A wet mount in saline of freshly passed faecs is prepared and
examined at once under the microscope.
 Microscopic examination of stools for amoebae requires
technical expertise. False results are common, especially
when examination is done by a non-expert.

39. 2.5 Criteria for rejection of
specimens:
 Missing or inadequate identification.
 Insufficient volume.
 Specimen collected in wrong collection tube.
 Contamination.
 Inappropriate transport and storage.
 Unknown time delay.

40. Thank You
Ahmad Al-Natour