Clinical Assessment Methods Flashcards

A potassium of 6.8 mmol/L is reported on a specimen with visible hemolysis and a normal ECG. What is the most likely explanation?

Answer: Pseudohyperkalemia from in vitro hemolysis

Lysed RBCs release intracellular potassium, falsely elevating results.

A delta check flags a patient's hemoglobin that dropped from 14.2 to 8.1 g/dL in 6 hours with no reported bleeding. What should be done first?

Answer: Investigate for specimen misidentification or IV contamination

Large unexplained deltas suggest preanalytical errors such as wrong patient or dilution.

Which preanalytical error is suggested by markedly elevated glucose with low sodium and potassium near normal in a sample drawn from an arm with an IV line?

Answer: Contamination with dextrose IV fluid

Drawing above a dextrose infusion raises glucose and dilutes other analytes.

A serum sample left unseparated at room temperature overnight will most likely show:

Answer: Decreased glucose

Cells continue glycolysis, consuming glucose about 5–7% per hour.

Which result pattern suggests EDTA contamination of a chemistry specimen?

Answer: High potassium, very low calcium

K2/K3EDTA adds potassium and chelates calcium.

Prolonged tourniquet application (over 1 minute) most commonly causes falsely increased levels of:

Answer: Total protein and protein-bound analytes

Hemoconcentration raises large molecules and protein-bound substances.

An ammonia specimen should be handled in which way to ensure accurate assessment?

Answer: Placed on ice and analyzed promptly

Ammonia rises in vitro from cellular metabolism, so samples are iced and run quickly.