ASCP Phlebotomy Technician Certification Practice Exam 2026 - Free Phlebotomy Practice Questions and Study Guide

The requirement for chilled specimens is crucial for certain assays to ensure the accuracy and reliability of laboratory results. This is particularly relevant for substances that can be affected by temperature changes, which can lead to alterations in their concentration or activity.

In the case of gastrin, ammonia, catecholamine, and lactic acid, these substances exhibit instability if not properly handled. For example, ammonia is highly susceptible to elevation in concentration if allowed to warm; it is crucial that the specimen is chilled immediately after collection to halt metabolic processes and prevent false increases in levels. Similarly, catecholamines are sensitive to light and temperature, with chilling helping to preserve their integrity during transport. Lactic acid must also be kept cold to prevent continued metabolism within the blood sample, which can lead to falsely high results.

Hence, the correct choice includes assays that require chilling to maintain test accuracy, highlighting the importance of specimen handling in laboratory medicine.