Final answer:
The first morning urine sample is most commonly used for urine pregnancy testing due to its higher concentration of hCG. Clean catch method is also utilized to maintain sample purity.
Explanation:
The collection method most frequently used for urine pregnancy testing in the physician's office is the first morning urine sample. This is because the concentration of hCG (human chorionic gonadotropin), a hormone detected in early pregnancy, is usually highest in the first morning void. Thus, it provides a more accurate result. Additionally, a clean catch urine sample is another common method used to prevent contamination.
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