Chemo-pathology

1. INTRODUCTIONTO CHEMICAL
PATHOLOGY

2. CHEMICAL PATHOLOGY
BY
DR. BOT,YAKUBU SUNDAY
DEPARTMENT OF MEDICAL LABORATOTRY
SCIENCE
FACULTY OF ALLIED SCIENCES
KAMPALA INTERNATIONAL UNIVERSITY-
WESTERN CAMPUS
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3. MODULE 1:
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4. 4
Learning outcomes:
After completing this section you should be
able to:
•Describe the kinds of analytes that are
measured using clinical chemistry tests
•Identify different types of biologic specimens
that may be used for testing
•Describe how the results of tests are
interpreted

5. General outline
• Laboratory Medicine
• Chemical Pathology
• Chemical Pathology Services
• Classical Requests in Chemical Pathology
Laboratory
• Classification of Chemical Pathology
Service

6. General outline
• Acquisition of Chemical Pathology Data
• Reference Ranges and Units

7. Laboratory Medicine
• Is a Clinical Science and Discipline solely
devoted to the Quantitative or Qualitative
assessment of any substance which can be
assayed in any type of biological fluid of
any animal species including humans for
either medical or research purposes.

8. Laboratory Medicine
Case scenario 1
A 77-year old man presents to the
emergency department with fever and
chills. He has had multiple urinary tract
infections in the past and feels that this is
”another one”. He has a history of
diabetes mellitus, Type 2 with diabetic
nephropathy and chronic kidney disease.
Physical examination is notable for an ill-

9. Laboratory Medicine
-appearing man with right flank tenderness.
How will the Medical Laboratory impact this
patient care.

10. Laboratory Medicine
DISCUSSION
Confirm clinical diagnosis
Urinalysis
Guide appropriate dosing of anti-biotics
Dose adjustment for reduced GFR based
on variables including serum creatinine

11. Laboratory Medicine
DISCUSSION cont.
Guide selection of appropriate antibiotic
therapy
With multiple course of treatment in the
past , there may be issues with anti
biotic resistance.

12. Laboratory Medicine
Today’s clinical Laboratory is a complex
arena offering an expansive menu of tests
which continues to grow.
Note that more than 70% of the objective
data in a patient’s medical record comes
from the clinical laboratory.

13. Laboratory Medicine
Therefore, Laboratory Medicine (Clinical
Pathology) Is the medical discipline that
specializes in the performance, reporting
and interpretation of clinical laboratory
tests in the provision of high quality
patient care.
Solely, to provide evidence based
scientific testing techniques to support
patient care.

14. WHO IS
“Laboratory Medicine”
 Comprised of Pathologists, Medical
Laboratory Scientists, and Medical
Laboratory Technicians

15. Laboratory Medicine cont.
 Blood Bank/ Apheresis
Chemistry/ immunoassay
Hematology and coagulation
Urinalysis fluid analysis and medical
microscopy.
Cytogenetics
Endocrinology
Immuno serology

16. Laboratory Medicine cont.
 Microbiology (Bacteriology, Virology, and
Parasitology)
Molecular Pathology
Tissue Typing /HLA
Toxicology

17. Chemical test is performed on body
fluids:
Cerebro-spinal fluids
blood samples
urine samples
Pleural fluid
Synovial fluid
saliva
Sweats

18. CHEMICAL PATHOLOGY
• Pathology is the scientific study of the
cause, origin, and nature of disease,
including the changes occurring as a result
of disease.
• Chemical Pathology (also known as
Clinical Biochemistry or Clinical Chemistry)
is the branch of pathology concerned with
the biochemical basis of disease, and the
application of biochemical and molecular
techniques in diagnosis.

19. CHEMICAL PATHOLOGY
• An allied subspecialty of Chemical
Pathology is Metabolic Medicine which
deals with metabolic disease in all its
manifestations.
• Chemical Pathology is the branch of
pathology dealing with the biochemical
basis of disease and the use of
biochemical tests and or molecular
techniques for diagnosis and
management.

20. CHEMICAL PATHOLOGY
WHAT IS THE ROLE OF CHEMICAL
PATHOLOGY IN HEALTH CARE
 First there is the provision of a reliable
analytical service, for example measuring
serum electrolytes, indices of liver
function, hormones, drugs and
tumor markers in hundreds of patient
samples every day.

21. Chemical Pathology cont..
 Many of these analyses are performed
on automated analyzers, usually
operated by Medical Laboratory
Scientists,
Chemical Pathology is therefore
applicable in:

22. • Diagnosis: tests can be used to help
differentiate between various possibilities
in the differential diagnosis based on the
initial history and examination when the
patient first presents.
• Screening: detection of disease before it
is clinically evident, e.g. testing all infants
at birth for a specific inherited disease
(phenylketonuria, thyroid deficiency)
• Monitoring: following the progression
of disease processes, checking against

23. • Monitoring: following the progression of
disease processes, checking against
adverse drug effects (e.g. hypokalaemia
with diuretic therapy), or response to
therapy (glucose levels in diabetes
mellitus).
• Prognosis: providing information on
disease susceptibility, e.g. cholesterol to
predict heart disease.

24. DATA ACQUISITION AND
PROCESSING
Completing the requisition form
Transmitting the request form to the laboratory
Labelling the specimen appropriately which
must be from the appropriate container
Linking the specimen with the request form
Recording the raw test result data
Computing the results

25. DATA ACQUISITION AND PROCESSING
cont.
Linking the results with the request form
Linking latest result with the past results
Edit the reports
Transmitting the report to the appropriate
address
Linking the report to the Patient’s notes
Storing a copy of the report in the laboratory
file

26. FACTORS THAT MAY AFFECT LABORATORY
RESULTS
ANALYTICAL :(specificity-whether any
similar chemical interferes with the test and
sensitivity –referring
to the detection limit of the machine) eg if
detection limit is low, early diagnosis of PSA
can be missed
Physiological factors: The collection of the
right specimen, storage conditions and or
treatments etc

27. REFERENCE VALUES
Osita-Oleribe Princess 27
Values expected from a healthy person (‘normal
values’ or use for medical decision level-MDL)
Test result for a giving analyte is compared
with the values in order to see if the test result
falls outside the range of the expected values.
Such reference values are reported either in
conventional units or S.I units.
Eg chloride (Cl-) 98-108mEq/L or 98-
108mmol/L
(hypochloremia or hyperchloremia).

28. Reference values cont.
Another example is Serum Sodium (Na+) level reference
value is 135-148 mEq/L or 135-148mmol/L
(hyponatremia or hypernatremia).
NB: Analytes in clinical chemistry are often grouped as:
 Hepatic (liver profile)
Electrolyte panel
Comprehensive metabolic panel
Basic metabolic panel
Lipid profile

29. Importance of reference values
Provide the necessary
context for medical
analysis and diagnosis
Without it, no basis for which
to make a diagnosis and take
a clinical decision, treat etc
 Provides support for interpretation of
numerical pathology reports

30. Important to note:
1.A normal result in one laboratory may mean abnormal in another
(hence, always compare your result with the performing lab.
reference values)
 Lab. Variability do occur due to differences in testing equipment,
chemical reagents used, analysis techniques applied etc.
2.A normal result does not promise health: though a good sign, not a
guarantee. Especially in early disease state.
3.abormal result may not necessarily mean you are sick:(you may
be one of those few whose result falls outside the range of
healthy majority.

31. This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License
Mean and Standard Deviation
MEAN

32. TABLE 1:UNITS OF EXPRESSION OF SOME
ANALYTES IN CHEMICAL PATHOLOGY
IONS,SALT
AND
MINERALS
Unit of
expression
SMALL
ORGANIC
MOLECULES
Unit of
expressio
n
LARGE
ORGANIC
MOLECULES
Potassium,
Sodium,
Chloride,
Bicarbonate
Magnesium
Calcium,
mEq/L or
mmol/L
mg/dl or
mmol/L
Glucose,
Cholesterol,
urea,
Creatinine,
Bilirubin,
Triglycerides
Digoxin
Phenytoin
Vancomycin
Salicylates
Ethanol
mg/dl or
mmol/L
ng/ml
µg/ml
mg/dl
g/dl
Protein
Albumin
ALT
AST
ALP
Lipoprotein
(HDL,LDL)
g/dl or
g/L
U/L
mmol/L
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33. CONCLUSION
Tutorials:
Q1. Define body analytes and
classify them accordingly.
Q2. What are reference values and of what
relevance are they?
Q3.List the types of body fluids used in
chemical pathology laboratory and
highlight their sources.
• Thank you for listening
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