American Medical Technologist (AMT) Practice Exam

The correct answer is based on the unique requirements for testing phenylketonuria (PKU), particularly in newborn screening. For PKU testing, blood specimens are often collected on special filter paper known as Guthrie cards. This method allows for the preservation of the sample, making it suitable for analysis by mass spectrometry or microbiological methods.

This technique is particularly significant because phenylketonuria is a genetic disorder in which the body cannot breakdown phenylalanine, leading to a buildup that can cause serious health issues if not managed from a young age. The use of filter paper is standard practice in newborn screening programs, enabling early detection and intervention.

Other tests mentioned do not utilize this method. Hematocrit, glucose tolerance tests, and lipid panels typically require standard blood collection and do not involve the specialized filter paper used for PKU testing. Therefore, the PKU test is specifically distinguished by its need for this type of sample collection, emphasizing the importance of targeted screening in medical practice.