Introduction To Chemical Pathology Flashcards
What is the function of the chemical pathologist
To study the changes of the chemical constitution and the biochemical mechanisms of the body as a result of a disease
What is chemical pathology
The systematic study of biochemical processes with health and disease and the measurement of the constituents of body fluids to facilitate diagnosis of diseases
What are the various disciplines in clinical laboratory testing
Immunology
Virology
Genetics
Clinical biochemistry
Cytology
Clinical microbiology
Histopathology
Hematology and transfusion
What are the roles of chemical pathology in healthcare
Diagnosis
Treatment
Screening
Prognosis
Monitoring
What is a sample
Material for a patient for the investigation of the condition or disease
The quality of the results depends on the quality of …………..
The specimen/sample
What are some samples taken for analysis
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)
What are some of the analytes tested for in the lab
Blood glucose
Electrolytes
Proteins and enzymes
Hormones
Lipids
Other metabolic substances
What is an analyte
A substance whose concentration is being tested for in the lab
Name some lipid profile tests
TG
TC
LDL
HDL
VLDL
List some tumor marker tests
PSA
CA 125
Mention some therapeutic drug monitoring test
Digoxin test
Blood tubes include a preservative and are color coded consistent with the anticoagulant used
True or false
True
What information do the color coded tubes communicate to you
It tells you which preservative is found the tube
What is the preservative used in a gray cap tube
Fluoride oxalate (for blood glucose analysis)
What is the function of fluoride oxalate in the gray colored tube
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
What is the preservative in the purple (mauve) cap tube
EDTA (to run glycated Hb - also used to monitor glucose levels in diabetic patients)
What is the preservative in the green cap tube
Heparin (for acid base analysis)
What is the function of the yellow cap tube (gel separator tube)
Used to separate the whole blood into serum and plasma
What are some factors to consider before collecting specimen
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
What is venostasis
It is the prolonged use of tourniquet which raises plasma levels of analytes
How are samples preserved in transit
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
How are samples stored
Refrigeration keeps sample stable for about 7 days
For long term, store at <-80 degrees Celsius to prevent substantial degradation
What are other names of chemical pathology
Medical biochemistry
Clinical chemistry
Clinical biochemistry
Pure blood chemistry
Physiological chemistry
………. is at the center of all laboratory testing
The patient
…………. is the clinical decision reached by a clinician after initial history and examination and laboratory investigations
Diagnosis
………… is the application of medicine to treat/cure a diagnosed condition
Treatment
…………… is the use of diagnostic testing to evaluate disease changes such as progression or response to therapy
Monitoring
…………….. is used to investigate for presence of disease in an apparently healthy population or detection of disease before it is clinically evident
Screening
…………… 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
Prognosis
List some examples of liver function tests
AST
ALT
ALP
GGT
BIL
TP
List some bone profile tests
Calcium
Phosphate
ALP
ALB
List some thyroid function tests
TSH
Free T4
Give some examples of acid base tests
pH
pCO2
H2CO3
PO2
Give some examples of carbohydrate metabolism tests
FBG
RBG
Ketone bodies
HBA1C
List some examples of cardiac markers
Troponin
CK
Give some examples of sex hormone tests
Estrogen
Testosterone
Give some examples of adrenal hormone tests
Aldosterone
Cortisol
Give some examples of specialized testing
Insurance testing
Occupational health testing
Drug of abuse testing
Environmental testing
List the stages of the biochemical investigation process
Clinical question/Biochemical answer
Request form with clinical data
Patient sample
Transit to lab
Reception and ID
Analysis
Quality control
Collation
Interpretation
Reporting
Every sample must be accompanied with a …………… for proper sample identification
Filled request form
Mention three things the filled request form of the sample should have
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
What are some factors to consider at the time of collecting the specimen
Specimen container
Identification of specimen
Appropriate selection of equipment
Patient posture
Venostasis
Site of venipuncture
Haemolysis
Not collecting specimen through lines or catheters
Point of care testing is also called
Ancillary testing
Alternative site testing
Near patient testing
Bedside testing
Physician office laboratory testing
Limited service laboratory testing
Out of laboratory testing
What is point of care testing
It refers to tests performed outside the hospital laboratory by untrained healthcare professionals or non-laboratory personnel (bedside, clinic, by patients themselves at home)
What are the categorizations of side room tests
Qualitative
Semi-quantitative or quantitative
Qualitative tests are mostly performed on ……..
Urine
An example of a qualitative test
Urine dipstick test
Quantitative tests are mostly performed on …………….
Blood specimen
An example of a quantitative test
Testing blood sugars using the glucometer
What are some advantages of SRT
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
What are some disadvantages of SRT
Analytical performance can be inferior to lab
Risk of poor operator competence
Risk of poor equipment maintenance
Cost per test is relatively more expensive
List some examples of qualitative commercially available POC tests
hcG
Drugs of abuse
Urinalysis
List some examples of quantitative commercially available POC tests
Glucose
Blood gases
Electrolytes
Creatinine
HBA1c
Troponin
Where are NPT devices useful
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)
Roche diagnostics is used for qualitative testing in ………….
Ethanol in either saliva or urine
