Health Screening

Excerpt

A health screening test is a medical test or procedure performed on members of an asymptomatic population or subgroup to assess their risk of developing a particular disease. We often think of screening for early diagnosis of cancer (such as Pap smears for cervical cancer or colonoscopy for colon cancer), but there are many other screening tests commonly used, for example, thyroid-stimulating hormone (TSH) for congenital hypothyroidism in newborns, cholesterol level for heart disease, urine drug screen for illicit drug use, or blood pressure for hypertension. Some screening tests are applied to a large segment of the population (eg, all adults older than 50), whereas others target a smaller subset (eg, pregnant women). Many screening tests are widely used in the United States. Healthcare providers can agree that early diagnosis of a life-threatening disease for which effective treatment is available is a positive step.

Unfortunately, health screening is complicated. Many articles on screening present a bewildering array of medical economics and biostatistics to make their points, and numerous credible organizations have offered their own (often differing) screening recommendations. The economic implications of screening are real. Even a single screening test applied to a large number (millions) of people can result in billions of dollars in annual health care expenditure. There are legitimate debates about sensitivity and specificity, disease prevalence, predictive values, lead-time bias, screening intervals, and appropriate cutoffs for positive or negative results. Recently, "shared decision making" has been suggested as an option when there is uncertainty about the advisability of a particular screening test (such as the prostate-specific antigen, or PSA, for the early diagnosis of prostate cancer). That may be possible if your patient is an educated professional. However, asking a patient without medical training to understand issues that challenge the intellect and judgment of most trained clinicians does not seem realistic. That the issue arises underscores the urgent need for improved screening tests.