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Clinical laboratory basic
1. Clinic Lab : Basic Overview
Training Design: Dorra Hung
2. Laboratory Roles & Responsibilities
The clinical lab provides diagnostic test data to aid in the detection,
diagnosis and treatment of disease. Data is used by physicians,
nurses, pharmacists and other healthcare professionals.
The responsibilities of the clinical lab include:
Correct identification, collection and processing of patient specimens
Accurate performance of testing
Timely reporting of results
Communication with physicians and other healthcare professionals
Analyst testing is used to help diagnose, monitor or treat disease
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3. Laboratory Workflow
There are six main steps in how a
sample flows through the lab
from order creation to final test
result.
1. Test is ordered.
2. Sample is collected
3. Sample is delivered to the lab.
4. Sample is processed.
5. Sample is analyzed.
6. Results are reported.
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4. Laboratory Specimens
Most common Laboratory Specimen Types:
Blood
Urine
Additional Laboratory Specimens:
Body fluids
Sputum
Stool
Tissue samples
Culture swabs
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8. Medical Examination
Objective is to get an answer about the health status of a patient
The physician determines on the basis of the anamneses, his clinical
examination and on the basis of additional known information an
Enquiry Examination Request
This is followed by the necessary preparation of the patient and blood
sampling
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9. Pre-Analytical
Common material for examination
Venous Blood (Serum or Plasma)
Capillary blood
Urine (Single shot or 24 hour collection)
Cerebrospinal fluid (CSF)
Puncture Fluids
Others, such as Faeces, Saliva, Gastric acid, Hair…..
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10. What is Blood?
Blood Composition 55% Plasma
Plasma Yellow, sticky liquid
Cells Transport of
Nutrients (proteins, fats,
carbon hydrates)
Hormones
44% Erythrocytes
Red blood cells
Contain Haemoglobin
O2 and CO2 transport
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11. What is Blood?
Blood Composition 0.1% Leucocytes
Plasma White blood cells
Cells Protection against
bacteria
viruses
0.9% Thrombocytes
Platelets
Coagulation at injuries
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12. Sample containers - What do we use?
Tube size (mm) Draw Volume
ID x Height (mL)
13 x 75 3.5
Red top Vacutainer® collection 13 x 100 4.0, 5.0,
tubes are used for 16 x 100 5.0, 6.0, 7.0, 8.0
serum determinations 16 x 100 8.5
in chemistry. Stopper Coagulant Use
They contain NO coagulant. color
Lavender EDTA Hematology
The grey and red speckled SST™ Light Blue Sodium citrate Coagulation
tube at left (“tiger top”) contains a Green Lithium Plasma
polymer gel for serum separation heparate chemistry
and has a Hemoguard™ tube Light Green Lithium Serum
heparate + gel chemistry
closure. Grey Sodium citrate Glucose
testing
The Vacutainer® at right has a
conventional tube stopper,
Tubes are now made of plastic to
help protect personnel from injury
and bloodborne pathogens.
Vacutainer® and Hemogard™ are trademarks of Becton, Dickinson & Company.
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13. What samples do we analyze?
Phlebotomist draws
sample
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14. Plasma versus Serum
Blood to which an anticoagulant has been Blood to which no anticoagulant has
added will not clot. Blood cells will settle to the been added will clot. Blood cells get
bottom of the tube leaving plasma at the top of caught in the clot leaving serum
the tube. behind.
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15. Pre-Analytical
Possible Influences
Age, gender
Genetic influences
Nutritional influences
Pregnancy
Biorhythm (diurnal rhythm causing analytical fluctuations)
Muscular mass, body weight
Physical activity or inactivity
Psychological stress (fear for blood collection, surgery)
Use of medicines
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16. Pre-Analytical
Disturbing Influences
Sample collection (body position, venous congestion, ….)
Sample condition (haemolytic, lipemic, icteric)
Normal serum obtained from an individual in good health is usually
clear, pale yellow in color. However, the color of the patient’s serum
may appear different for various reasons such as disease or improper
handling of the blood specimen.
Lipemia (Lipe) results from increased levels of lipoproteins associated
with triglycerides, and it can cause the serum to appear white.
Hemolysis (Heme) is caused usually by the release of hemoglobin
from ruptured red blood cells during sample collection and/or sample
handling. This interference can cause the serum to appear red.
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17. Pre-Analytical
Icterus (Icte) is the result of increased levels of bilirubin, and it can cause
the serum to appear yellow.
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19. Pre-Analytical
After the centrifugation if the sample was without anticoagulant the supernatant
fluid is SERUM otherwise is plasma .
As anticoagulants they use EDTA K3 , EDTA K2 , Heparin, Citric acid 9:1, Citric
Acid 4:1 NaF and others.
If we use plasma we must know the type of the anti-coagulant due to different
interferences f.e.
Ca , Na , Fe , ALP ...
21. Pre-Analytical
Some photometric assays may be influenced by the presence of these
abnormal serum colors and the reliability of the test results may be
decreased.
haemolysis can cause analytical interferences such as high K+
caused by release from erythrocytes, or can interfere with the
measuring technique (photometry)
Inadequate sample transport
Wrong centrifugation
Inadequate sample storage (Bilirubin)
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22. Pre-Analytical
Different type of sample collection in commercially available blood collection
systems (Beckton Dickinson Vacutainer, Sarstedt Monovetten, …..)
Tube with additional Extraction of Application Colour-
Anti-Coagulation agent coding
Whole blood (without Serum Clinical Chemistry, Serology, Red
agent) Immunochemistry
Heparin Plasma Clinical Chemistry Green
EDTA Plasma Haematology, Special Lilac
Chemistry, Immunochemistry
Citrate Plasma Coagulation tests Bleu
Na-Fluoride / K-Oxalate Plasma Glucose, Lactate Grey
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23. Pre-Analytical
Serum
Plasma versus Serum 30-45 minutes clothing (preferably
in the dark)
10-15 minutes centrifugation
@ 1000-1500 g
Plasma
Blood to which an anticoagulant has been
added will not clot. Blood cells will settle to the
Blood to which no anticoagulant has
been added will clot. Blood cells get
Immediate 10-15 minutes
bottom of the tube leaving plasma at the top of caught in the clot leaving serum
the tube. behind.
centrifugation @ 1000-1500 g
For internal use only
Page 7 Jan-07 Velemirov / Twisk EU Sales Training
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24. Pre-Analytical
Sample transport and storage
Properly packed
Transport must be save
Bio hazardous material
4 hours stable @ 15-25 oC
Closed to avoid evaporation
24 hours stable @ 4-8 oC
Dry ice, cool packs, refrigerator, etc.
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25. Pre-Analytical
Example: Potasium
Plasma is recommended for rapid centrifugation
Use only serum or plasma from single patients
Sample preparation (heparin plasma)
Centrifuge within 30-45 minutes after collection
Erythrocytes produce Homocysteine, which continues after
sampling
Store on ice if centrifugation within 30-45 minutes is not possible
Store plasma at -20 oC if sample can not be measured within 48
hours
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27. Analytical
Adequate test methodology
Standard Operating
Procedure
Understandable
Traceable
Routine test must be
Easy to be executed
Reliable
Low risk on failure
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28. Statistical Quality Control
Samples with known concentration
Low
Medium
High
As part of the daily routine
Begin of the run
Middle in the run
End of the day
Random
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31. Patient Result
Test Report
Demographic information
Patient name, Patient ID, Lab number
Sample matrix, Visual distortions
Date, Time
Sample collection, Arrival in the lab, Time of analyses
Analytical results
Test name, Unit, Reference values, Comments (high/low, diluted,
duplicates, ……)
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32. Analytical Results
Expected Values
Reference Range
Normal values
Based on a large pool
of healthy persons
Differences between
Children vs. adults
Male vs. female
Serum vs. plasma
Population
Biorhythm
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33. Diagnose
After checking the reliability of the analysis
Analytical range
Statistical Quality control
Pre-analytical and analytical disturbances
Plausibility of the result
Compared with previous results
Fit with the situation of the patient
DIAGNOSE
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34. Methods of Clinical Chemistry
Photometry
Chemiluminence
Potentiometry (ISE)
Electrophoresis
Nephelometry
γ- COUNTER
Mass absorption
Osmometry
HPLC
TLC
Coagulation
...
35. Optical Density A = - log 10 T
Photometry A= ε x L x C
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47. Direct potentiometry : This is the simplest method of making ion-
selective electrode measurements. The electrodes are immersed in
a test solution and the electrode potential is measured directly with
a millivolt meter. The concentration is then related directly to this
measurement by reading the answer from a calibration graph of
concentration versus millivolts.
Indirect potentiometry : Dilution of the sample (less volume, less
problems, less interventions
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49. Pre-analytical factors that affect serum proteins
concentrations
1)Time of the day
2)Position
3)Exercise
4)Fasting vs non fasting
5)Medications
6)Time of year (season)
7)Age and gender
8)Geographic location
9)Venipuncture technique
10)Sample handling and storage
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50. Patient Result
Test Report
Demographic information
Patient name, Patient ID, Lab number
Sample matrix, Visual distortions
Date, Time
Sample collection, Arrival in the lab, Time of analyses
Analytical results
Test name, Unit, Reference values, Comments (high/low, diluted,
duplicates, ……)
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51. Auto-validation
Automatic
Limits defined by the lab
Delta checks
Quality control with Westgard rules
Messages from the systems
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