MLPAO Clinical Chemistry Fundamentals 2

Question 1

In the measurement of serum electrolytes, which technology uses ion-selective electrodes (ISE)?

Accepted Answer

Potentiometry

Answer

Potentiometry is the electrochemical technique that uses ion-selective electrodes to measure electrolyte concentrations. ISE technology measures the electrical potential difference generated across a membrane selective for a specific ion, providing direct measurement of ion activity.

Question 2

What is the clinical significance of an elevated serum amylase level?

Accepted Answer

Acute pancreatitis

Answer

Elevated serum amylase is most commonly associated with acute pancreatitis. Amylase is released from damaged pancreatic acinar cells into the bloodstream. However, amylase can also be elevated in other conditions such as salivary gland disorders and intestinal obstruction.

Question 3

Which specimen type is preferred for most clinical chemistry analyses?

Accepted Answer

Serum from a red-top tube

Answer

Serum collected in a red-top (no additive) tube or serum separator tube (SST) is preferred for most clinical chemistry analyses. Serum lacks fibrinogen and clotting factors, providing a cleaner matrix that minimizes interference with many analytical methods.

Question 4

What is the Henderson-Hasselbalch equation used to calculate in clinical chemistry?

Accepted Answer

Blood pH from bicarbonate and pCO2

Answer

The Henderson-Hasselbalch equation calculates blood pH from the ratio of bicarbonate concentration to dissolved CO2 (pCO2). The equation is pH = pK + log([HCO3-]/[0.03 × pCO2]), and it is fundamental to understanding acid-base physiology.

Question 5

Which condition is characterized by elevated serum bilirubin with a predominantly unconjugated (indirect) fraction?

Accepted Answer

Hemolytic anemia

Answer

Hemolytic anemia causes elevated unconjugated (indirect) bilirubin because the excessive breakdown of red blood cells overwhelms the liver's capacity to conjugate bilirubin. In contrast, obstructive and hepatocellular conditions typically elevate conjugated (direct) bilirubin.

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO Clinical Chemistry Fundamentals 2