Introduction To Chemical Pathology

Question 1

What is the function of the chemical pathologist

Answer 1

To study the changes of the chemical constitution and the biochemical mechanisms of the body as a result of a disease

Question 2

What is chemical pathology

Answer 2

The systematic study of biochemical processes with health and disease and the measurement of the constituents of body fluids to facilitate diagnosis of diseases

Question 3

What are the various disciplines in clinical laboratory testing

Answer 3

Immunology
Virology
Genetics
Clinical biochemistry
Cytology
Clinical microbiology
Histopathology
Hematology and transfusion

Question 4

What are the roles of chemical pathology in healthcare

Answer 4

Diagnosis
Treatment
Screening
Prognosis
Monitoring

Question 5

What is a sample

Answer 5

Material for a patient for the investigation of the condition or disease

Question 6

The quality of the results depends on the quality of …………..

Answer 6

The specimen/sample

Question 7

What are some samples taken for analysis

Answer 7

White blood (plasma or serum)
Urine (spot collection - early morning, random, midstream or timely)
Body fluids (CSF, gastric fluid)
Solid tissues (hair and nail clippings potentially for drugs and heavy metal analysis)

Question 8

What are some of the analytes tested for in the lab

Answer 8

Blood glucose
Electrolytes
Proteins and enzymes
Hormones
Lipids
Other metabolic substances

Question 9

What is an analyte

Answer 9

A substance whose concentration is being tested for in the lab

Question 10

Name some lipid profile tests

Answer 10

TG
TC
LDL
HDL
VLDL

Question 11

List some tumor marker tests

Answer 11

PSA
CA 125

Question 12

Mention some therapeutic drug monitoring test

Answer 12

Digoxin test

Question 13

Blood tubes include a preservative and are color coded consistent with the anticoagulant used
True or false

Answer 13

True

Question 14

What information do the color coded tubes communicate to you

Answer 14

It tells you which preservative is found the tube

Question 15

What is the preservative used in a gray cap tube

Answer 15

Fluoride oxalate (for blood glucose analysis)

Question 16

What is the function of fluoride oxalate in the gray colored tube

Answer 16

It prevents glucose metabolism (inhibition of glycolysis) in the tube. Anaerobically, the RBC can metabolize glucose in the sample thus giving you likely false reduced glucose levels

Question 17

What is the preservative in the purple (mauve) cap tube

Answer 17

EDTA (to run glycated Hb - also used to monitor glucose levels in diabetic patients)

Question 18

What is the preservative in the green cap tube

Answer 18

Heparin (for acid base analysis)

Question 19

What is the function of the yellow cap tube (gel separator tube)

Answer 19

Used to separate the whole blood into serum and plasma

Question 20

What are some factors to consider before collecting specimen

Answer 20

Patient’s diet (glucose, lipids)
Patient’s current medication (oral contraceptives, cough mixtures- could increase sugar concentration)
Time of day (diurnal variation) - iron and cortisol
Specimen container

Question 21

What is venostasis

Answer 21

It is the prolonged use of tourniquet which raises plasma levels of analytes

Question 22

How are samples preserved in transit

Answer 22

Blood gas analysis samples (PCO2 and PO2) must be kept at 4 degrees from the time sample is drawn or plasma is separated from cells)
Place the sample in a container of ice
Specimen from bilirubin and carotene must be kept from sunlight and fluorescent light to avoid photodegradation
Specimen for hormonal assays such as gastrin, rennin and parathyroid hormones must be separated from the cells in a refrigerated centrifuge

Question 23

How are samples stored

Answer 23

Refrigeration keeps sample stable for about 7 days
For long term, store at <-80 degrees Celsius to prevent substantial degradation

Question 24

What are other names of chemical pathology

Answer 24

Medical biochemistry
Clinical chemistry
Clinical biochemistry
Pure blood chemistry
Physiological chemistry

Question 25

………. is at the center of all laboratory testing

Answer 25

The patient

Question 26

…………. is the clinical decision reached by a clinician after initial history and examination and laboratory investigations

Answer 26

Diagnosis

Question 27

………… is the application of medicine to treat/cure a diagnosed condition

Answer 27

Treatment

Question 28

…………… is the use of diagnostic testing to evaluate disease changes such as progression or response to therapy

Answer 28

Monitoring

Question 29

…………….. is used to investigate for presence of disease in an apparently healthy population or detection of disease before it is clinically evident

Answer 29

Screening

Question 30

…………… is the prediction of the clinical outcome of a disease or providing information on disease susceptibility. Eg. cholesterol can predict the risk of coronary artery disease

Answer 30

Prognosis

Question 31

List some examples of liver function tests

Answer 31

AST ALT ALP GGT BIL TP

Question 32

List some bone profile tests

Answer 32

Calcium Phosphate ALP ALB

Question 33

List some thyroid function tests

Answer 33

TSH Free T4

Question 34

Give some examples of acid base tests

Answer 34

pH pCO2 H2CO3 PO2

Question 35

Give some examples of carbohydrate metabolism tests

Answer 35

FBG RBG Ketone bodies HBA1C

Question 36

List some examples of cardiac markers

Answer 36

Troponin CK

Question 37

Give some examples of sex hormone tests

Answer 37

Estrogen Testosterone

Question 38

Give some examples of adrenal hormone tests

Answer 38

Aldosterone Cortisol

Question 39

Give some examples of specialized testing

Answer 39

Insurance testing Occupational health testing Drug of abuse testing Environmental testing

Question 40

List the stages of the biochemical investigation process

Answer 40

Clinical question/Biochemical answer Request form with clinical data Patient sample Transit to lab Reception and ID Analysis Quality control Collation Interpretation Reporting

Question 41

Every sample must be accompanied with a …………… for proper sample identification

Answer 41

Filled request form

Question 42

Mention three things the filled request form of the sample should have

Answer 42

Patient’s name, address and DOB Time and date of sampling The requests Other information which might help interpretation (Eg. Patient’s sex, LMP, drug monitoring information) Requesting clinician’s name

Question 43

What are some factors to consider at the time of collecting the specimen

Answer 43

Specimen container Identification of specimen Appropriate selection of equipment Patient posture Venostasis Site of venipuncture Haemolysis Not collecting specimen through lines or catheters

Question 44

Point of care testing is also called

Answer 44

Ancillary testing Alternative site testing Near patient testing Bedside testing Physician office laboratory testing Limited service laboratory testing Out of laboratory testing

Question 45

What is point of care testing

Answer 45

It refers to tests performed outside the hospital laboratory by untrained healthcare professionals or non-laboratory personnel (bedside, clinic, by patients themselves at home)

Question 46

What are the categorizations of side room tests

Answer 46

Qualitative Semi-quantitative or quantitative

Question 47

Qualitative tests are mostly performed on ……..

Answer 47

Urine

Question 48

An example of a qualitative test

Answer 48

Urine dipstick test

Question 49

Quantitative tests are mostly performed on …………….

Answer 49

Blood specimen

Question 50

An example of a quantitative test

Answer 50

Testing blood sugars using the glucometer

Question 51

What are some advantages of SRT

Answer 51

Spot/Small blood volume/ Turn around time (relatively short analysis time with immediate results) Early treatment and shortens patient’s wait Ease of use (can be performed by less trained personnel or by the patient themselves) Promoter stabilization of life-threatening crisis (eg. drug overdose) Closer therapeutic management Better patient compliance with therapy (diabetes, hyperlipidemia) Reduces repeat clinic/patient visits and length of stay in the hospital

Question 52

What are some disadvantages of SRT

Answer 52

Analytical performance can be inferior to lab Risk of poor operator competence Risk of poor equipment maintenance Cost per test is relatively more expensive

Question 53

List some examples of qualitative commercially available POC tests

Answer 53

hcG Drugs of abuse Urinalysis

Question 54

List some examples of quantitative commercially available POC tests

Answer 54

Glucose Blood gases Electrolytes Creatinine HBA1c Troponin

Question 55

Where are NPT devices useful

Answer 55

Accident and emergency (diagnosis of acute MI with a whole blood troponin NPT device, drug overdoses - plasma p’mol, cocaine) Drug addiction clinics (alcohol breath test, roche diagnostics) General practice, out-patient, clinics and wards (using urine dipstick testing for screening patients - UTI, urine protein) Neonatal care and adult intensive care (Neonatal units: determination of blood bilirubin using bilirubinometers) Patient self testing (eg. pregnant self-testing using over-the-counter pregnancy test kits)

Question 56

Roche diagnostics is used for qualitative testing in ………….

Answer 56

Ethanol in either saliva or urine