NHA Phlebotomy Certification Practice Exam

When drawing an infant screening card along with O2 levels, bilirubin, and DNA, which should be drawn first?

1. DNA

2. O2 levels

3. Bilirubin

4. Infant screening card

The correct answer is: O2 levels

When performing a blood draw that includes various tests such as oxygen levels, bilirubin, DNA, and an infant screening card, the priority is to prevent contamination and ensure the accuracy of the results. Oxygen levels should be drawn first because they require immediate processing to avoid alterations in the results due to exposure to air. Levels of oxygen in the blood can fluctuate rapidly, making it critical to obtain this measurement as early as possible in the process. Bilirubin testing specifically requires care in handling and timing because bilirubin can be affected by light exposure, which can degrade the sample if not properly managed. Similarly, DNA samples and the infant screening card can be collected afterward without the risk of contamination that could affect the results of the oxygen levels. Prioritizing the draw in this manner ensures that the values obtained are the most reliable for clinical interpretation.