Biochemical Laboratory Techniques Practice Test

A 45-year-old man presents to a clinic for a routine health screening. He reports a history of intravenous drug use several years ago. A rapid screening test for HIV is positive. A confirmatory test is ordered, which involves separating viral components by size on a gel, transferring them to a membrane, and then using patient serum to detect antibodies that bind to these specific components.

A 9-year-old boy is evaluated for intellectual disability, a long narrow face, prominent jaw, and large ears. His family history is significant for a maternal uncle with similar features. To confirm the suspected diagnosis of Fragile X syndrome, a genetic test is performed. The technique involves digesting the patient's DNA with a restriction enzyme, separating the fragments by gel electrophoresis, and using a labeled DNA probe corresponding to the FMR1 gene.