Which statement about pregnancy screening immunoassays is true?

• A. Immunoassays will use reagent anti-hCG to react with patient hCG.
• B. A random urine specimen is the preferred specimen for pregnancy screening tests.
• C. Internal controls provided within the kit will assess if the patient's specimen was collected correctly.
• D. External quality control is not needed with these methods

Answer: (A)

Immunoassays for pregnancy screening detect the hormone hCG by using antibodies that specifically bind to it. The test includes reagent anti-hCG that interacts with hCG in the patient’s urine or serum, producing a signal that indicates pregnancy when hCG is present. This binding is the core mechanism by which the assay signals a positive result, so this statement is true.

Regarding the other points: random urine isn’t always the preferred specimen; first-morning urine is often recommended because it is more concentrated and can improve sensitivity. Internal controls in the kit check that the assay ran properly and reagents are functioning, not that the patient collected the specimen correctly. External quality control is still needed to ensure accuracy across laboratories.