Delayed separation of serum from red blood cells can lead to falsely elevated enzyme activities. Which option best represents this preanalytical error?

Delayed separation of serum from red blood cells can lead to falsely elevated enzyme activities. Which option best represents this preanalytical error?

• A. Fasting status
• B. Ice storage
• C. Delayed separation of serum from cells
• D. Light exposure

Answer: (C)

Delayed separation of serum from cells causes enzymes to be released from blood cells into the serum, inflating measured activities. After blood is drawn, cells such as platelets, leukocytes, and red cells can continue to function and sometimes leak enzymes if the serum remains in contact with them before centrifugation. This ongoing release or minor cell lysis leads to higher enzyme readings than were present in the serum at collection, which is exactly a preanalytical error. To prevent this, separate the serum promptly by centrifugation after clotting, and store or transport the sample under appropriate conditions; if delays are unavoidable, refrigerate to slow cellular processes. Fasting status generally doesn’t cause a false elevation in enzyme activities, ice storage would reduce such changes rather than cause them, and light exposure affects only certain photosensitive analytes, not this specific preanalytical issue.

Delayed separation of serum from cells causes enzymes to be released from blood cells into the serum, inflating measured activities. After blood is drawn, cells such as platelets, leukocytes, and red cells can continue to function and sometimes leak enzymes if the serum remains in contact with them before centrifugation. This ongoing release or minor cell lysis leads to higher enzyme readings than were present in the serum at collection, which is exactly a preanalytical error. To prevent this, separate the serum promptly by centrifugation after clotting, and store or transport the sample under appropriate conditions; if delays are unavoidable, refrigerate to slow cellular processes. Fasting status generally doesn’t cause a false elevation in enzyme activities, ice storage would reduce such changes rather than cause them, and light exposure affects only certain photosensitive analytes, not this specific preanalytical issue.