To assure an accurate ammonia level result, the specimen should be processed as:

• A. Incubated at 37 C prior to testing
• B. Spun and separated immediately, tested as routine
• C. Spun, separated, iced, and tested immediately
• D. Stored at room temperature until tested

Answer: (C)

Ammonia in blood is highly labile and prone to change after collection due to ongoing cellular metabolism and bacterial activity. To obtain an accurate result, processing must halt these processes as quickly as possible. Spinning and separating removes cells that can generate ammonia, placing the sample on ice slows enzymatic and bacterial activity, and testing immediately prevents any further in vitro production or changes. Incubating at body temperature would speed up ammonia generation, and storing at room temperature allows ongoing changes or degradation, both risking inaccurate results. Therefore, the best approach is to spin, separate, iced, and test immediately.