Lecture 5 - Clinical instrumentation Flashcards
Types of biomedical scientists: INFECTION SCIENCES
- medical microbiology - identification of micro-organisms causing disease and their antibiotic treatment
- virology - identification of viruses, associated diseases and monitoring the effectiveness of vaccines.
Types of biomedical scientists: BLOOD SCIENCES
- clinical chemistry - analysis of body fluids and toxicology studies
- transfusion science - determination of donor/recipient blood compatibility, ensuring blood banks are sufficient
- haematology - form and functions of blood and related diseases
- immunology - understanding the immune system and its role in combating disease.
Types of biomedical scientists: CELLULAR SCIENCES
- histopathology - microscopic examination of diseased tissue samples
- cytology - best known for cervical smear screening, but also covers other cellular analysis.
Types of biomedical scientists: GENETIC & MOLECULAR PATHOLOGY
- genetics - study of genes and hereditary variations in genes
- molecular pathology - study and diagnosis of disease through examination of tissues and fluids at molecular level.
Waht is Clinical chemistry?
- Clinical chemistry refers to the biochemical analysis of body fluids.
- It uses chemical reactions to determine the levels of various chemical compounds in bodily fluids.
- Several simple chemical tests are used to detect and quantify different compounds in blood and urine, the most commonly tested specimens in clinical chemistry.
State some techniques used in clinical chemistry
Techniques such as:
- Spectrophotometry
- Immunoassays
- Electrophoresis
are also used in clinical chemistry to measure the concentration of substances such as:
Glucose, lipids, enzymes, electrolytes, hormones, proteins, and other metabolic products present in human blood and urine.
Specimens tested in clinical analysis: SERUM
- Most common specimen tested;
- Obtained by centrifugation of coagulated blood;
- Doesn’t contain blood cells or clotting factors, but contains electrolytes, hormones, antigens, antibodies, and other substances such as drugs, microbes, or proteins.
Specimens tested in clinical analysis: Plasma
- Obtained by centrifugation of uncoagulated blood;
- Contains blood cells, clotting factors, glucose, electrolytes (such as sodium, magnesium, calcium, chloride), hormones, and proteins (such as albumins, fibrinogen, and globulins).
Specimens tested in clinical analysis: Urine
The collection container usually contains a preservative.
Specimens tested in clinical analysis: CEREBROSPINAL FLUID (CSF):
- Is a clear fluid present in the brain and spine which is largely similar to blood plasma, though it differs as it doesn’t contain any protein.
- Analysed to rule out meningitis.
What are the key parameters of carbohydrates tested and their significance?
CARBOHYDRATES -
Glucose levels indicate the body’s efficiency in metabolizing glucose. Fasting and random glucose levels in blood help in the diagnosis of endocrinological disorders such as hypoglycemia (low blood sugar) and diabetes.
What are the key parameters of lipids tested and their significance?
present in different forms as body fat, as part of cell membranes, and as sterols such as cholesterol.
-Diagnosis of liver and heart disease in humans.
What are the risk factors associated with high levels of lipids in blood?
present in different forms as body fat, as part of cell membranes, and as sterols such as cholesterol.
-Diagnosis of liver and heart disease in humans.
What are the key parameters of enzymes tested and their significance?
ENZYMES - Measuring the levels of enzymes released by organs into the blood can indicate problems with a particular organ.
Examples:
1) Creatine kinase in the body indicate heart or skeletal muscle damage
2) Alanine aminotransferase or aspartate aminotransferase levels indicate liver disorders
3) Amylase and lipase signal pancreas inflammation or pancreatic carcinoma.
What are the key parameters of hormones tested and their significance?
Measuring levels of hormones can help determine if the corresponding glands are functioning correctly or are hyperactive/ hypoactive.
Examples:
1) Cortisol is a hormone secreted by the adrenal glands;
2) Thyroxine (T4) and thyroid stimulating hormone (TSH) are secreted by the thyroid gland;
3) Follicle stimulating hormone (FSH) and growth hormones are secreted by the pituitary gland.
What are the key parameters of proteins tested and their significance?
The concentration of proteins in the body can be indicative of nutritional and metabolic disorders and some forms of cancer.
Example:
1) Total protein and albumin linked to liver or kidney disease;
2) Globulin levels and the ratio of albumin to globulin can help detect infection, inflammation, autoimmune disease, and some forms of blood cancer.
What are the key parameters of electrolytes tested and their significance?
The levels of various electrolytes such as Na, Cl, K, Ca, bicarbonate, phosphorus, and Mg in the body can help diagnose some kidney and metabolic disorders.
What are the key parameters of metabolites tested and their significance?
Levels of urea, nitrogen and creatinine in the blood are indicators of kidney function. Similarly, uric acid levels can signal kidney disease, gout, and damage to other tissues.
Chemistry analysers: Cobas e501
- Up to 1000 tests/hr;
- fully automated;
- performs over 110 measurements of proteins, enzymes, substrates and electrolytes, direct anti-globulin tests (DATs), and therapeutic drug monitoring (TDMs).
Chemistry analysers: Cobas e601
- 175 tests/hr;
- fully automated;
- immunoassay tests using Electro ChemiLuminescence (ECL) technology.
Chemistry analysers: Cobas 6000 modular analyser:
- 15 million tests per annum
- 220 parameters consolidated on one system
- Customised to fit the labs needs
- Core module + Cobas e501 + Cobas e601.
Cobas6000 analyser series- clinical chemistry menu
Other methods –dipstick tests
Describe Urinanalysis (US)
What is it used for?
- Used as a screening and/or diagnostic tool to detect substances or cellular material in the urine associated with metabolic disorders, renal dysfunction or urinary tract infections (UTI).
- Often, substances such as protein or glucose will begin to appear in the urine before patients are aware that they may have a problem.
How can urine be assesssed?
Urine may be assessed both at the bedside (dipstick) and in the laboratory (microscopy, culture, sensitivity and urinary electrolytes).
Urine for laboratory analysis must be transferred quickly and at the correct temperature otherwise breeding ground for contaminants.
