Certified Respiratory Therapist Practice Exam

What is the required control for verification of blood gas analyzer calibration?

1. Only low-level control

2. Only high-level control

3. Three materials with known values

4. One control sample

The correct answer is: Three materials with known values

Verification of a blood gas analyzer's calibration involves the use of three materials with known values—often referred to as quality control samples. This approach is essential to ensure the accuracy of the analyzer's results across a range of conditions that it may encounter in clinical practice. Using three control materials allows respiratory therapists to assess the performance of the analyzer at various points along the measurement spectrum. This is crucial because it helps identify any drift or shifts in accuracy that may occur over time, particularly as the equipment is used in a clinical setting. The three materials are typically designed to represent low, medium, and high values for the parameters being tested, such as pH, carbon dioxide, and oxygen levels. By comparing the analyzer's readings to the known values of these control materials, clinicians can confirm that the device provides reliable and accurate results. If one or more control results fall outside of the acceptable range, it signals that calibration may be necessary or that there may be an issue with the analyzer itself. Thus, the use of three control materials is a comprehensive and standard practice in ensuring the integrity of blood gas analysis.