CBET Laboratory and In-Vitro Diagnostic Equipment

Question 1

A hematology analyzer using the Coulter principle counts and sizes blood cells by measuring changes in what physical property as cells pass through an aperture?

Accepted Answer

Electrical impedance

Answer

Light scattering angle

Answer

Fluorescence emission

Answer

Magnetic field distortion

Question 2

A blood gas analyzer's pO₂ electrode consistently reads 10–15% lower than expected across all QC levels. After confirming the sample path is clear, what is the most likely cause?

Accepted Answer

A fouled or expired Clark electrode membrane

Answer

Air bubbles trapped in the QC sample syringe

Answer

Incorrect barometric pressure input

Answer

Contaminated sodium reference electrode

Question 3

During PM on a clinical centrifuge, a BMET notices excessive vibration during a spin cycle. What should be checked FIRST?

Accepted Answer

Rotor balance and proper symmetrical tube loading

Answer

Carbon brushes on the drive motor

Answer

Speed control potentiometer calibration

Answer

Timer relay contacts

Question 4

Which regulatory standard specifically mandates that clinical laboratories run quality control specimens at defined intervals before reporting patient results?

Accepted Answer

CLIA '88 (Clinical Laboratory Improvement Amendments)

Answer

ISO 9001 General Quality Management

Answer

FDA 510(k) premarket notification

Answer

NFPA 99 healthcare facilities standard

Question 5

A spectrophotometer used for hemoglobin measurement is checked and found to have a wavelength accuracy error of ±5 nm at 415 nm. Why is this clinically significant?

Accepted Answer

415 nm is the Soret band of hemoglobin, where absorbance changes sharply with wavelength, causing large measurement errors

Answer

415 nm is outside the visible spectrum and the detector sensitivity drops off

Answer

Hemoglobin only absorbs in the infrared range, so UV errors compound

Answer

A 5 nm shift causes the blank reading to exceed the sample reading

Question 6

A point-of-care blood glucose meter consistently reads 18% higher than the central lab reference method for the same patient samples. After confirming patient prep was correct, the MOST likely cause is:

Accepted Answer

The test strip lot has an incorrect calibration code or expired strips

Answer

The patient has polycythemia, falsely elevating capillary glucose

Answer

The meter's Bluetooth sync introduced a data offset

Answer

The central lab method is known to underestimate in ICU patients