Lab tests go under a critical microscope
■ Experts point out that good tests used badly can lead to bad medicine.
By Victoria Stagg Elliott — Posted Nov. 1, 2004
Sometimes patients are better off if physicians refuse to order a test, according to a panel discussion at last month's annual convention and scientific sessions of the American College of Osteopathic Internists in Chicago.
"Nearly every day in the medical realm, I see patients having blood drawn for one more test that appears to have no value in adding to their care," said Gerald Blackburn, DO, chief of infectious diseases at Botsford Hospital in Farmington Hills, Mich. He also chaired the panel discussion. "And a significant number of my outpatient consultations are to explain away for an hour why that test would have been better off never having been ordered."
It's not the that the tests are bad. To paraphrase Jessica Rabbit from the movie "Who Framed Roger Rabbit?" it's just that they've been drawn that way.
Doctors complain that good tests are sometimes being used on the wrong people, at the wrong time and for the wrong purpose, and that this can lead to much more than just excess cost. The tests may lead physicians down the garden path and expose patients to additional procedures with a greater risk of side effects or complications.
For example, Mark D. Baldwin, DO, a panelist and an internist in Columbus, Ohio, has had to spare patients from unnecessary treatments recommended on the basis of post-dialysis labs showing abnormalities. These abnormalities were most likely caused by the dialysis itself and very likely to normalize without medical intervention.
Dr. Blackburn has had to counsel couples distraught by positive herpes tests even though it's very hard to distinguish between type 1 and type 2. Herpes is extremely common, but each variant has different implications. A positive test, however, usually does very little to change clinical management, although it may damage a relationship.
Paul E. Wenig, DO, a rheumatologist from Troy, Mich., has been repeatedly faced with patients clutching the results of a slightly abnormal antinuclear antibody test -- ANA -- and information from the Internet suggesting they have lupus or some other autoimmune disease even though they're experiencing no symptoms.
"The positive ANA is diagnostic of nothing," he said. "But every patient who has a positive ANA comes into my office with a diagnosis because they go to the Internet. Then they come to my office saying, 'I have so-and-so disease.' "
These kinds of stories offer reasons for physicians to be more trusting of clinical judgment.
"Every year there's a new magic test," said Dr. Baldwin. "Don't forget to be a physician. We've invested a lot of time, effort and money in getting where we are. We need to use the skills we have."
The problem, though, is not just that the tests may be inappropriate for the situation. The results may not be properly interpreted because different laboratories may use different values.
Panelists said physicians should be familiar with the laboratories and order specific tests rather than whole panels.
"If you're not very specific about how you order tests, you will get some nonspecific tests that you can't explain," John R. Sutton, DO, an endocrinologist from Carson City, Nev. "Then they end up in my office, not because they have a dysfunction but because the labs look funny."
Physicians in the audience responded that the recommendations were good but encouraging doctors to rely more on clinical judgment was not the whole answer.
Doctors complained that there was enormous pressure to rely increasingly on lab tests from all sides, including their own liability concerns, patients, and third-party payers.
"You want to make sure you didn't miss anything so you order the test to prove what you thought was right even though you're clinically comfortable with what you said," said Ira B. Azneer, DO, an internist from St. Petersburg, Fla. "And then you get into to trouble."