An arterial blood specimen submitted for blood gas analysis was obtained at 8:30 am but was not received in the lab until 11 am. The technologist should:

• A. Perform test immediately upon receipt
• B. Perform only if the specimen was submitted in ice water
• C. Request a venous blood specimen
• D. Request a new arterial specimen be obtained

Answer: (D)

Arterial blood gas samples are extremely time-sensitive because ongoing metabolism in the sample after collection changes pH, pCO2, and pO2. If the specimen isn’t analyzed within a short window, its gas tensions and acidity will drift, making the results unreliable for diagnosing or managing the patient.

Because this sample was collected early in the morning but didn’t reach the lab until several hours later, the values would no longer reflect the patient’s true arterial status. The safest, most accurate course is to request a new arterial specimen be obtained and sent to the laboratory for prompt analysis.

The other options aren’t appropriate: testing a stale sample would give misleading results, substituting a venous sample isn’t acceptable for arterial gas interpretation, and relying on a delayed sample even with icing would still risk inaccuracy.