Clinical Biochemistry with correct answers

Clinical Biochemistry How is ECF volume tightly regulated? - correct answer - by adjusting water and electrolyte intake and excretion - goal is to maintain a constant osmolality Which two electrolytes give information about ECF osmolality? - correct answer Sodium and Chloride What compound gives information about serum pH? - correct answer bicarbonate What compounds give information about hormonal disturbances? - correct answer Calcium and Potassium Sodium - correct answer - principal extracellular cation - main indicator of ECF oncotic pressure - low values observed due to water retention with dilutes body fluids (hyponatremia) - high values commonly caused by dehydration (hypernatremia) What compound is the main indicator of ECF oncotic pressure? - correct answer Sodium Potassium - correct answer - major intracellular cation - important for membrane potential of muscle and nerve cells - low values (hypokalemia) are commonly caused by potassium loss (GI, Renal) - high values often result from renal insufficiency (hyperkalemia); affects muscle function and can trigger cardiac arrest with no warning Bicarbonate - correct answer - indicative of acid/base balance - must be monitored in conditions like DKA, along with glucose, pH, and electrolyte concentrations Calcium - correct answer - affects neuronal and muscular function; it is subject to tight hormonal control - low values (hypocalemia) indicates hormonal disturbances - high values (hypercalemia) indicates hormonal disturbances, but can also signify degradation of calcium stores in the skeleton through bone disease of cancer Phosphate - correct answer - stored in bones in the form of calcium phosphate - hyperphosphatemia can indicate degenerative bone disease; more commonly it is due to renal failure - hypophosphatemia is worrisome because it impairs glucose metabolism; with DKA phosphate levels must be monitored during treatment by glucose infusion Blood gases - correct answer CO2 concentration can be measured directly in an arterial blood sample - must be rushed to the lab immediately Metabolites in Serum - correct answer Glucose, Urea (BUN); Creatinine, Uric acid, direct and indirect bilirubin BUN values - correct answer blood urea nitrogen - serum increases in urea while urine urea decreases is indicative of kidney disease - reflects the balance between AA degradation/urea production and excretion - BUN increases after a protein rich meal Creatinine - correct answer -used along with serum urea as a measure of kidney function - released from muscles at a fairly constant rate; how much depends on age, gender, and muscle mass - increase in serum creatinine indicates a problem in glomerular filtration Uric acid - correct answer - high uric acid conc. are most often due to problems with renal excretion and predispose to gout Direct/Indirect bilirubin - correct answer - normally low in serum - high serum levels can lead to jaundice and neuronal damage Serum Proteins - correct answer Albumin, Globulins, C-Reactive Protein - normal serum protein conc is 7% Albumin - correct answer - produced by the Liver, makes up 50% of total serum protein - binding of hydrophobic molecules, calcium, and maintainance of oncotic pressure - low levels manifest as edema - common cause is liver disease C-Reactive Protein (CRP) - correct answer - secreted by the Liver, marked of acute metabolic response to an injury - levels rise 6 hours after injury, peak at 48 hrs, then decay slowly Serum enzyme markers for MI, and the timing of release - correct answer Myoglobin- occurs very quickly after MI; not specific to MI however Creatine Kinase - detectable fairly shortly after MI; peaks at ~2 days AST - released later than CK-MB; peaks ~3 days Troponins - most sensitive markers for MI; if after 12 hours, there are no troponins, there was no MI Cardiac LDH - released several days after MI; peaks ~4 days Alkaline Phosphate - correct answer - increased levels of alkaline phosphatase are indicative of bone or liver disease - obstruction of the gall duct with cause an increase in serum alkaline phosphatase - increase in bone remodeling (bone cancer, Paget's disease) will lead to increase in serum AP - liver disease will be distinguished with high bilirubin levels AST/ALT - correct answer - high levels in muscle and liver - in heart and other muscles, AST is 10x that of ALT - in liver, AST and ALT are approximately equal - high AST and low ALT indicate heart and other muscle damage - high AST and high ALT indicate liver damage Purpose of Urine Analysis - correct answer - Glucose: urine glucose signifies hyperglycemia - Bilirubin: conjugated bilirubin in urine indicates biliary obstruction - Ketones: indicates fatty acid breakdown; occurs in uncontrolled diabetes or starvation - Protein: indicates renal disease Basic Metabolic Panel - correct answer - 8 tests for the analysis of kidney function, blood sugar, acid/base and electrolyte balances - glucose, calcium, sodium, potassium, chloride, CO2, BUN, creatinine Liver Function Tests - correct answer - bilirubin, AST, ALT, and alkaline phosphatase - elevated bilirubin and AP indicate blockage of bile duct - elevated AST and ALT indicate hepatocellular damage Kidney Disease - correct answer - both acute and chronic renal disease disturb the homeostasis of water and electrolytes - serum BUN and Creatinine will be elevated in renal failure -urine osmolality will be low in renal failure Diabetes management - correct answer - glycated hemoglobin HbA1c; indicates long term blood glucose levels - proteinuria- protein in the urine can detect the onset of diabetic nephropathy - C-peptide: amount of C-peptide in serum is good measure of endogenous production of insulin