Chemical Pathology Flashcards
What are the 4 roles of biochemical testing in the diagnosis of disease?
- Screen patients to detect disease
- Confirms presence of a suspected disease
- Monitors the progression or response to treatment for the disease
- Provides information on the prognosis and likely outcomes of the disease.
What are the 6 different specimen types used in the lab?
- Serum
- Plasma
- Urine
- Blood Gas
- Cerebrospinal fluid
- Whole Blood
What preanalytical variables affect results obtained in the lab?
- Incorrect labeling
- Wrong sample
- Haemolysis
What is the difference between plasma and serum?
Plasma has anticoagulants and blood cells are removed. The serum is clotted.
What happens during haemolysis and why should it be avoided?
Haemolysis is the breakdown of red blood cells and it disrupts the integrity of blood.
What are the benefits of point-of-care tests?
It is quick and results are available immediately.
What are the 2 different ways of sample collection?
- Urine Containers
2. Blood Tubes
What is bilirubin?
Bilirubin is the compound that is formed from haem proteins.
How is unconjugated bilirubin taken to the liver?
Unconjugated bilirubin travels in the blood to the liver via a carrier protein called albumin
What is added to unconjugated bilirubin to make it water-soluble?
Glucuronic acid
How is bilirubin excreted from the body?
Stercobilin in stool or urobilinogen in urine
What is the cause of Jaundice?
Increase in bilirubin
Name 3 causes of prehepatic jaundice
- Incompatible blood group
- Abnormal Haemoglobins
- RBC defects
Name 3 causes of intrahepatic jaundice
- Alcohol
- Infective Agents
- Hypoxia
Name the cause of posthepatic jaundice
Cholestasis - Obstruction of Bile Ducts
How does neonatal jaundice occur?
Neonate has high levels of RBC with shorter life span. Therefore, high levels of bilirubin because liver is immature.
What enzyme is liver specific?
ALT (Alanine aminotransferase)
What 2 liver enzymes are indicators of liver cellular damage?
ALT + AST
Alanine aminotranferase + aspartate aminotransferase
What liver enzymes increase with obstructive liver disease?
ALP + GGT
Alkaline Phosphatase + Gamma-glutamyltransferase
Where is insulin secreted?
Beta-cells in pancreatic Islets of Langerhans
Discuss the metabolic actions of insulin
- Glucose levels rise
- Glucose binds to GLUT-2 receptor on beta-cells of Islets of Langerhans
- Glucose is metabolized inside the cell and ATP is released
- ATP closes the K-channel, K remains inside cell. Therefore, depolarizes the cell
- Calcium enters the cell and insulin is released
What are the 3 counter-regulatory hormones to insulin?
- Glucagon
- Cortisol
- Growth Hormone
What is the difference between Type 1 and Type 2 diabetes?
Type 1 - Autoimmune disease in which the pancreas does not secrete enough insulin
Type 2 - insufficient insulin is secreted to prevent hyperglycaemia
What is the difference between primary and secondary diabetes?
Primary - decrease in insulin secretion or insulin action
Secondary - due to other diseases that increase the counter-regulatory hormones to insulin
