Challenge Your Exam Readiness With Our Free Phlebotomy Practice Questions

Air bubbles equilibrate rapidly with arterial blood, artificially raising pO₂ and lowering pCO₂. The most critical immediate step is to expel visible bubbles from the heparinized syringe, then cap it tightly to maintain an anaerobic environment. Gentle mixing prevents microclots that can clog analyzer capillaries. Rapid transport—often on ice—slows cellular metabolism and preserves gas tensions and pH when analysis cannot be immediate. Option B captures this sequence. Light protection (Option A) is relevant to photosensitive analytes, not blood gases. Allowing the sample to clot (Option C) is incorrect; ABGs are whole-blood tests in anticoagulated syringes. Leaving an air space (Option D) worsens gas exchange artifacts. Additional best practices include verifying positive patient and specimen identification, documenting collection time and oxygen delivery settings, and analyzing within the laboratory’s validated stability window. Proper ABG handling is a high-yield exam topic because small preanalytical errors can lead to misinterpretation of respiratory status and inappropriate ventilatory or oxygen therapy adjustments.