Tutorial 2 Flashcards
What are the main groups of proteins found in normal plasma?
Major groups include:
* Albumin
* Globulins
* Fibrinogen
* Enzymes
* Hormones
* Antibodies
These groups play various roles in maintaining physiological functions.
What factors influence the plasma concentration of an enzyme?
Factors include:
* Production rate
* Clearance rate
* Tissue damage
* Hormonal regulation
* Genetic variations
Not all enzymes have a specific function in plasma.
What are the functions of major plasma proteins?
Functions include:
* Maintaining oncotic pressure
* Transporting substances
* Immune responses
* Clotting processes
* Buffering pH levels
Each protein group serves distinct physiological roles.
What is the significance of elevated levels of total protein?
Elevated levels may indicate:
* Dehydration
* Chronic inflammation
* Multiple myeloma
Monitoring total protein levels helps in diagnosing various conditions.
What is the significance of diminished levels of albumin?
Diminished levels may indicate:
* Liver disease
* Nephrotic syndrome
* Malnutrition
Albumin levels are critical for assessing liver and kidney function.
Describe the basic structure of immunoglobulins.
Immunoglobulins consist of:
* Two heavy chains
* Two light chains
* Variable region
* Constant region
Immunoglobulins are essential for immune function.
Define ‘monoclonal protein’ (paraprotein).
Monoclonal protein is:
* A type of antibody produced by identical immune cells
* Often associated with diseases like multiple myeloma
Paraproteins can indicate the presence of certain malignancies.
List diseases in which a monoclonal protein may be present.
Diseases include:
* Multiple myeloma
* Waldenström’s macroglobulinemia
* Chronic lymphocytic leukemia
The presence of monoclonal proteins can aid in the diagnosis.
What are the enzymes commonly measured in plasma for disease diagnosis?
Commonly measured enzymes include:
* Alkaline phosphatase (ALP)
* Alanine aminotransferase (ALT)
* Aspartate aminotransferase (AST)
* Lactate dehydrogenase (LDH)
* γ-glutamyltransferase (GGT)
* Creatine kinase (CK)
* Lipase
* Troponins
Each enzyme is linked to specific organ functions and disease states.
What is the purpose of reference intervals in laboratory tests?
Reference intervals are used for:
* Evaluating test results
* Comparing patient results to population averages
* Determining normal vs abnormal ranges
Reference intervals may vary by laboratory and are essential for accurate diagnosis.
What is the traditional method for serum protein electrophoresis?
The traditional method involves:
* Applying serum to a solid matrix
* Using an electric current for separation
* Staining to reveal protein bands
This method has been largely replaced by capillary zone electrophoresis.
What is capillary zone electrophoresis?
Capillary zone electrophoresis is:
* A technique that measures protein concentration as it passes through a capillary
* Produces profiles similar to traditional electrophoretograms
This method allows for more precise and rapid analysis of serum proteins.
True or False: Reference intervals are standardized across all laboratories.
False
Reference intervals can differ between laboratories and may change over time.
What is Chemical Pathology?
A branch of diagnostic medicine that focuses on the quantification and analysis of chemical and biochemical solutes/compounds; ions, proteins, enzymes, lipids, etc.
What is the significance of solute/compound profiles in the body?
The normal activity and turnover of cells causes the release of solutes/compounds at a rate proportional to cell number, metabolism, and cell death/turnover.
What does a change in the amount of analytes indicate?
It may indicate a pathological change such as increased cell death, metabolic change, or cell/tissue adaptation.
What types of specimens can be tested in chemical pathology?
- Serum/plasma
- Whole blood (capillary, venous, arterial)
- Urine
- Sputum (phlegm/saliva)
- Cerebrospinal fluid
- Aspirates (synovial fluid, interstitial fluids, amniotic fluid)
Who performs diagnostic testing in medical laboratories?
Registered medical laboratory scientists and technicians.
Why is it important not to test for everything?
Every test has a cost; unnecessary tests increase the workload and overall cost of diagnosis.
What is the difference between serum and plasma?
- Plasma: Fluid component of blood with anticoagulants
- Serum: Plasma without coagulation factors
What are reference intervals?
Defined as ~95% or 2 standard deviations from the mean of the normal reference population.
What factors can cause variation in reference intervals?
- Age
- Sex
- Normal health status (e.g., pregnancy)
- Laboratory differences
What constitutes a mild fever?
38 – 38.9 °C; may indicate early infection, recovery, or low-risk infection.
What constitutes a moderate fever?
39 - 39.9 °C; a stronger indicator of potential active infection.
What constitutes a major fever?
> 40 °C; indicates a severe and potentially dangerous infection.
What is the normal range for pancreatic lipase in adults?
13-60 U/L.
What does an elevated pancreatic lipase activity indicate?
It may indicate acute pancreatitis, with varying severity based on the level.
How does half-life relate to proteins and enzymes?
It refers to the turnover or breakdown of compounds in circulation.
What is the diagnostic value of troponin tests post-myocardial infarction?
Troponin tests (TnT/TnI) have the most diagnostic value, with differing half-lives indicating recovery.
What are isoenzymes?
Structural variants of an enzyme that catalyse the same reaction but may be produced by different cells.
What are the major plasma proteins?
- Albumin
- Globulins (α, β, γ)
- Coagulation proteins
What does Serum Protein Electrophoresis (SPE) do?
Separates major serum proteins into distinct visual bands based on net charge.
What does a narrow band in SPE indicate?
Proteins in this region are very homogeneous.
What does an increase in the α1 peak indicate?
It may occur in acute inflammation or malignancy.
What does a decrease in the albumin peak indicate?
It may indicate loss of albumin, reduced production, or health status.
What can cause an increase in the β1 peak?
Increased production of transferrin, e.g., in iron deficiency anaemia or pregnancy.
What does an increase in the γ peak indicate?
Hypergammaglobulinaemia, such as in inflammation or cirrhosis.
What is the relationship between CK and CK-MB?
CK quantifies all creatine kinase while CK-MB specifically quantifies the cardiac isoenzyme.
Fill in the blank: An increase in the β2 peak occurs in inflammation from the increased production of ______.
complement proteins.
True or False: Troponins (TnT/TnI) are myocardial infarction specific.
False; they are cardiac-specific but not MI-specific.
What does an increase in the β2 peak indicate?
Inflammation from increased production of complement proteins
What condition is indicated by a decrease in the β2 peak?
Autoimmune disease, which may activate and deplete complement
What is the significance of performing electrophoresis on plasma instead of serum?
Fibrinogen would be present in the β2 region
What is Serum Protein Electrophoresis (SPE)?
A method for learning about proteins in the circulation
What is a key advantage of modern SPE over gel electrophoresis?
Quicker and easier to perform
What types of proteins can SPE identify?
Major serum protein groups in very high concentration
What conditions is SPE particularly useful in diagnosing?
- Plasma cell myeloma
- Monoclonal gammopathy of undetermined significance (MGUS)
What is plasma cell myeloma?
A cancer of plasma cells resulting in large amounts of a monoclonal antibody (paraprotein)
What is a characteristic finding in the γ region for plasma cell myeloma?
A narrow peak consistent with excess production of a monoclonal antibody
What does hypogammaglobulinaemia indicate in plasma cell myeloma patients?
Susceptibility to infection due to very low γ region
What causes hypoalbuminaemia in plasma cell myeloma?
Thought to be related to the extent of myeloma proliferation
What is nephrotic syndrome?
An excessively porous filtration barrier in the nephrons of the kidneys
What is the primary cause of hypoalbuminaemia in nephrotic syndrome?
Loss of albumin through the filtration barrier
What causes the increase in the α2 region in nephrotic syndrome?
Accumulation of α2-macroglobulin due to loss of smaller proteins
What is cirrhosis?
Fibrosis/scarring of the liver in chronic liver disease
What leads to hypoalbuminaemia in cirrhosis?
Loss of hepatic parenchymal tissue
What complicates the increase in γ-globulins in cirrhosis?
Collateral circulation secondary to portal hypertension
What are the types of alternative methods for protein/enzyme analysis?
- Colourimetric Assay
- Enzymatic Assay
- Immunological Assay
What is a Colourimetric Assay used for?
Detecting a colour change in the presence of the target protein
What does an Enzymatic Assay measure?
Quantifies the enzyme based on its activity (U/L)
What does an Immunological Assay utilize?
Target protein-specific antibodies for detection
What is the significance of the AST:ALT ratio in liver disease?
Usually >2.0 in alcoholic liver disease, ~1.0 in acute hepatitis
What does a major elevation (>10x URL) of ALT indicate?
Acute hepatitis, drug-induced liver necrosis
What are the common interpretations for GGT elevation?
- > 10x URL = Cholestasis, alcoholic liver disease
- 5-10x URL = Acute hepatitis, chronic hepatitis
What does an elevation in ALP typically indicate?
- Cholestasis
- Osteomalacia/rickets
- Paget disease of bone
What is the significance of elevated lipase?
Indicates pancreatic tissue damage (e.g., pancreatitis)
What does an elevated TnT level indicate?
Cardiac myocyte damage (e.g., myocardial infarction)
What is the interpretation of AST elevation without ALT elevation?
Excludes liver disease
What does the presence of both AST and LDH elevation indicate?
Non-specific tissue damage, may be consistent with haemolysis
What is the diagnosis for Patient D based on test results?
Myocardial Infarction
What might a major elevation in lipase indicate for Patient F?
Acute pancreatitis
What might a mild elevation in lipase indicate for Patient E?
Chronic pancreatitis
