Clinical Chemistry Flashcards
What are the three main areas in clinical chemistry?
- Routine Chemistry
- Routine Urinalysis
- Special Chemistry
What is the routine chemistry area?
testing in this area determines the concentration of various chemical analytes (glucose, cholesterol, triglycerides, electrolytes, serum proteins, cardiac enzymes and urea)
Which department is the largest and most automated in chemistry?
routine chemistry
What are some tests done under special chemistry?
serum electrophoresis, therapeutic drug monitoring, toxicology studies and quantitation of hormone levels
What are some types of specimens that are submitted for chemistry tests?
- blood, urine, feces, CSF, sweat and other body fluids
What are the tubes that are collected for chemistry tests?
SST (serum separator tube) and PST (plasma separator tube)
What is glucose broken down from?
Dietary carbohydrates
What maintains the blood glucose level?
Insulin
What is the range described as for the control of blood glucose with insulin?
Narrow range
What are the two terms associated with blood glucose concentration?
Hyperglycaemia
Hypoglycaemia
What’s the difference between hyperglycaemia and hypoglycaemia?
Hyper = increased glucose in blood Hypo = decreased glucose in blood
What is most often associated with diabetes Mellitus?
Hyperglycaemia
Blood collected after fasting for at least 8 hours but not more than 16 hours = what type of test?
Fasting blood glucose
Blood collected at any time = what kind of test?
Random blood glucose
What is temporary hyperglycaemia?
When the blood glucose level of someone is high due to a carbohydrate-rich meal
How long does it take an individual’s blood glucose to return to normal during temp. hyperglycaemia?
within 2 hours
What test requires no fasting, then a 50g glucose load, and then the blood is collected an hour after?
gestational diabetes screen
When can you take the gestational diabetes screen test?
Between 24-28 weeks of gestation
What test is performed if fasting blood glucose is high?
glucose tolerance test
What is the glucose load for the glucose tolerance test? Then when is blood collected?
75g – After 2 hours.
What test is performed when the gestational screen is high?
glucose tolerance for gestational diabetes mellitus
What’s the key difference between the glucose tolerance test and the glucose tolerance test for GDM?
samples are collected at 1 hour and 2 hours post consumption
What test is done to check dietary compliance and insulin use in diabetics?
HbA1c (glycosylated or glycated hemoglobin)
What is a glycosylated hemoglobin?
when blood glucose binds to hemoglobin
The rate of formation of glycosylated hemoglobin is ____ to the blood glucose concentration.
proportional
What electrolytes are most likely tested for?
sodium, potassium, chloride, and bicarbonate ion (measured in CO2)
How are excess amounts of electrolytes excreted from the body?
Through the urine by the kidneys
Which electrolyte is the primary extracellular ion?
Sodium (Na+)
What is sodium responsible for?
- The normal distribution of water between extracellular and intracellular compartments
- transmission of nervous impulses
What are the normal levels of Na+ in serum/plasma?
quite high
What are the normal levels of K+ in serum/plasma?
low
When comparing levels of K+ in the RBC vs. plasma/serum, how much more concentrated are RBC?
25x higher
What is the second most prevalent extracellular ion?
Chloride (Cl-)
What is the function of chloride?
maintaining water balance
What is the most common form by which carbon dioxide is transported in the blood?
bicarbonate ion (HCO3-)
How is the acid-base balance determined?
by measuring CO2- and pH of the blood
What are the two most common plasma lipids that are tested for?
cholesterol and triglycerides
What are lipoproteins?
when cholesterol or triglycerides bind to proteins making them water soluble
What is the difference between LDL and HDL?
LDL = “bad” because when cholesterol is in the LDL form, it is more likely to attach to arterial walls
HDL is “good” as it protects against atherosclerosis
What is the two types of cholesterols?
Low-density (LD) lipoprotein
High-density (HD) lipoprotein
What lipid tests are done without fasting?
- triglycerides
- total cholesterol
- HDL
- LDL
What is protein used for in the body?
For growth, repairing tissues and maintenance of body weight
What type of protein makes up 2/3 of the total protein population?
albumin
What makes up the 1/3 of proteins?
globulins (α1, α2, β, γ)
What does the serum protein electrophoresis (SPE) test do?
it separates proteins into five fractions and determines the portion of each.
- area under the peak = that protein’s concentration
Waste products = UREA and CREATININE
Where are they produced?
Urea = liver creatinine = muscles
What does elevated levels of urea and creatinine usually indicate?
renal disease
How is the creatinine clearance test done?
Urine is collected over a period of 12 to 24 hours
Then determination of creatinine in serum/plasma and urine is done.
What is the creatinine clearance testing?
measure the glomerular filtration rate (GFR)
How does gout occur?
when the concentration of uric acid in blood is above a certain level –> crystallization in the joint
When does jaundice occur?
When the levels of bilirubin in plasma is 2-3x higher than normal amount.
What does high concentrations of enzymes in the blood indicate?
tissue damage or tumours
What are the few enzymes ordered?
alkaline phosphatase (ALP), amylase, aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT) and lactate dehydrogenase (LD)
