A sexually active woman presents with amenorrhea and vaginal spotting, along with left adnexal tenderness. What test should be prioritized?

In this scenario, a sexually active woman presenting with amenorrhea, vaginal spotting, and left adnexal tenderness indicates the need to rule out a possible ectopic pregnancy or ongoing intrauterine pregnancy. A urine pregnancy test should be prioritized because it is a quick, non-invasive, and effective first step in evaluating the situation.

If the test is positive, it provides immediate insight into the patient's reproductive status and leads to further necessary investigations or interventions based on whether the pregnancy is ectopic or intrauterine. Additionally, a positive test in the context of the symptoms may indicate the need for urgent medical evaluation due to the risk of complications.

While a complete blood count could provide information on anemia or infection, it doesn't address the immediate concern of potential pregnancy status. A pelvic ultrasound is certainly an important follow-up test that can provide detailed images of the reproductive organs, but it requires confirmation of pregnancy first. A flat plate of the abdomen is less relevant in this context, as it does not directly assist in evaluating the most pressing concern of the patient's reproductive health. Prioritizing the pregnancy test aligns with the clinical presentation and the need for timely decision-making in this case.