California Phlebotomy Certification Practice Exam

If a glucometer reading shows 250 mg/dL, what could have caused an inaccurate first result if a second test is within the reference range?

1. Faulty glucometer

2. Too little blood was used

3. Too much blood was used

4. Wrong test strip was used

The correct answer is: Too much blood was used

If a glucometer reading shows 250 mg/dL initially and a subsequent test falls within the reference range, one possible reason for the discrepancy could be that too much blood was used in the first test. Glucometers are calibrated to work with a specific volume of blood, and using an excessive amount can lead to dilution of the glucose sample, which might produce a false high reading. When too much blood is applied, the accuracy of the glucometer could be compromised, as the mechanics of how the device measures glucose can be affected by the sample's volume. This can cause the meter to misinterpret the sample, leading to a higher glucose reading than might actually be present in the patient's blood. The other options, while potentially related to inaccuracies, do not specifically address the issue of volume in the same way as using too much blood. Understanding the correct volume needed for testing is critical to ensure the accuracy of the glucometer readings.