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- MEDICINE, Page 79Unbelievable Blood Tests
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- Laboratory reports are often misleading or downright mistaken
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- Medical testing centers have plenty of business these days
- -- perhaps more than they can properly handle. Prompted by fears
- of everything from AIDS and Lyme disease to high cholesterol,
- record numbers of people are lining up to give a blood sample
- and get back the good news, or bad. Too frequently, though, the
- news is just plain wrong. Several recent studies have revealed
- disturbing sloppiness or simple error in the way some blood
- tests are conducted and interpreted.
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- Among the worst offenders are public cholesterol-screening
- programs. Such centers, already a familiar sight in supermarkets
- and shopping malls in some parts of the U.S., may become even
- more common in the wake of a Government report issued last week.
- The report recommended a low-fat, low-cholesterol diet for
- everyone, not just those at risk for heart disease.
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- In a study of four public cholesterol-screening programs,
- published last week in the Journal of the American Medical
- Association, researchers found that only one produced accurate
- results consistently. The worst program was off the mark in
- almost 25% of the tests. A recent survey by the Department of
- Health and Human Services of such mass operations found that the
- "technicians" conducting the tests often had little or no
- training. More than half the people screened at 71 sites had
- their fingers squeezed, or "milked," to draw blood. This is
- known to dilute the blood with other fluids and produce an
- artificially low cholesterol reading. Says HHS inspector general
- Richard Kusserow: "Sometimes these operations looked more like
- a sideshow at a carnival." When blood is drawn in a medical
- setting by trained personnel, such error is less likely.
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- Lyme-disease tests can be inaccurate, even if carried out by
- experienced professionals. In a study reported in J.A.M.A.,
- blood from the same 101 people was taken to three testing
- centers. One lab found 23 cases of Lyme, but the second
- discovered 31 cases, and the third came up with 43. The main
- problem is a failure to standardize Lyme tests from lab to lab.
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- Tests for AIDS are more accurate, but problems have arisen
- in reporting the results. In a study of 13 labs in the Western
- U.S., researchers discovered that written test results often
- contained misleading information. Several lab forms incorrectly
- stated that a positive result meant only that one had been
- "exposed" to the virus. In fact, it means that one is infected.
- The authors of the report said such imprecision could confuse
- doctors, particularly those having little experience with AIDS.
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- Stricter U.S. regulations on laboratory procedures are
- scheduled to go into effect this year, and the Government will
- increase the number of labs being inspected nationwide from
- 12,000 to 300,000. But the task is enormous, and many labs may
- still escape the enhanced surveillance. So anyone troubled by
- the results of a cholesterol test or other blood exam might be
- smart to follow that age-old advice applying to medicine in
- general: get a second opinion.
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- By Andrew Purvis.
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- SLOPPY SCREENING
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- A U.S. study of public cholesterol testing found widespread
- unacceptable procedures:
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- % OF PEOPLE
- PROBLEM CITING PROBLEM
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- Patient's finger was improperly "milked" to obtain blood
- 58%
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- Staff did not change gloves with each new patient 50%
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- Staff did not wear gloves 35%
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- Work area was dirty 11%
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