Orlando Sellers found out he had high blood pressure while posing as a patient for a videotape being made by the Department of Veterans Affairs.

"I didn't know. But when the doctor took my blood pressure, it was extremely high -- 189 over 112," said Sellers, a 58-year-old human resources specialist at the VA Medical Center in Washington. "He said, 'That's high, let me check it again.' It was the same."

Despite strong evidence that tests like a blood pressure check every two years are worthwhile, barely 50 percent of U.S. adults receive the diagnostic and preventive screenings that many medical experts recommend. Several factors explain why many Americans remain unaware that they have hypertension, colorectal cancer, high cholesterol and other lethal conditions: the proliferation of recommended tests, doubts about the value of some once-standard exams and time demands that keep many doctors from performing systematic screening.

What to do? Experts say people should find a doctor who will schedule screenings as they become due -- or they should take over the scheduling themselves.

Too Much of a Good Thing?The merits of early detection and prevention of disease became especially clear in the 1950s and '60s, when childhood immunizations nearly eradicated a number of diseases, including measles. This success has had an ironic side effect: "As we have more entrenched screening, the risks seem less imminent, less of an immediate threat," said Amy Compton-Phillips, Kaiser Permanente's physician director for care management in Rockville. As a result, "it's harder to convince healthy patients that a screening is important."

Today's physicians are encouraged to screen patients for literally hundreds of conditions and diseases. This advice comes from specialists, from groups such as the American Cancer Society and from such respected standard-setters as the U.S. Preventive Services Task Force, a panel of experts that evaluates many components of primary care. The American Academy of Family Physicians endorses most of the task force's 20 or so screening recommendations -- and adds about 30 more. (For details, see http://www.ahrq.gov/clinic/uspstf/uspstopics.htmand http://www.aafp.org/x24996.xml.)

A further complication: The task force sometimes downplays screenings -- like breast self-exams and the prostate-specific antigen (PSA) test for prostate cancer -- that the medical establishment once supported enthusiastically.

The Doc and YouThe annual physical, long associated with a standard battery of tests that almost always produced a bill of good health, has fallen from favor in an era of managed care, evidence-based medicine and too-too busy physicians.

When David Sobel, a Kaiser Permanente physician, started practicing medicine 25 years ago, the routine exam was, well, routine. "Patients were tested annually -- chest X-ray, EKG, blood tests," he says. "But what it did was falsely reassured people and distracted them from the real things, much bigger things that have an impact on health, like stopping smoking."

Kaiser Permanente now stresses a preventive medicine package that varies based on each patient's age and sex. People with chronic conditions such as diabetes and hypertension get extra monitoring. "The notion that one size fits all is not appropriate," Sobel said.

This individualized approach calls for patients to play a larger role in their own care. Since learning of his high blood pressure, Orlando Sellers has enrolled in a pilot version of My HealtheVet, an Internet-dependent program that allows him to react quickly when he senses he may have eaten too much chocolate, fried food or soda.

"I've got a blood pressure cuff," said Sellers. "I enter the reading into the computer and it charts it. The graph gives me a good idea of where I am, and if I eat a very salty meal, I will notice that. . . . It lets me see I can't do certain things."

Along with providing online medical records, the program alerts patients when tests are due and points them to information about each test. "It's all about the patient taking responsibility," said Sellers.

This sort of outreach is not limited to large medical plans like Kaiser Permanente. At the Unity Healthcare community health clinic on 14th St. NW, providers remind their clients when they need to be seen. "We like our patients to come back several times a year," said Jose Aponte, the clinic's COO. "Last year 64,000 patients made 292,000 visits."

Finding the TimeIn a study published last year, Duke University physicians suggested why compliance with screening standards is so spotty: "Taken together, the time needed to meet preventive, chronic and acute care requirements vastly exceeds the total time physicians have available for patient care," they said.

Technology can help solve that time problem.

"Compliance is close to impossible without some kind of aid, a physician prompt from something like an electronic medical record," said Washington internist Peter Basch, who has invested in a record-keeping system that relies heavily on computerized data and minimally on paper records.

These systems can automatically alert a doctor -- on his hand-held computer device or on a monitor in the exam room -- that the patient he's seeing right now needs a particular test. "Pop-ups appear to remind us that the patient is due for, say, a pneumonia exam, something that typically goes unnoticed," Basch says.

But even physicians without a high-tech office can offer timely checkups, said Thomas Weida, a doctor in Hershey, Pa., who is a spokesman for the American Academy of Family Physicians. "There are lots of different systems for keeping track of necessary screenings. A simple flow sheet is very effective, and it's even more effective the closer it is to the top sheet" in the patient's chart, he said. "I'll often put screenings that might need to be done on the vital-sign sheet."

Still, Weida admitted that when a patient's acute health problems demand substantial time, it's tough to squeeze in a talk about screenings. That's why he suggests what he calls the 50,000-mile checkup at age 50. And while he often initiates this visit, he said he's pleased when a patient takes the lead. "I have many who come in and ask for it," Weida said. "Things change at 50, and it's a good time to go over what's recommended and to talk about things like aspirin therapy, weight, exercise. . . . That's when we'll talk about annual checkups. I may look at lifestyle and if all is fine, I'll say, 'See you back in three years.' " ·

Kathleen Phalen Tomaselli last wrote for the Health section about bed rest during pregnancy. Comments: health@washpost.com.