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Why Are Too Many Laboratory Tests are Ordered?

One of the main excuses that has been give to justify over utilization of laboratory tests has been that physicians practice defensive medicine and order every possible test to avoid a potential lawsuit. Another possibility is that physicians are weighing multiple diagnostic possibilities when they examine a patient and order enough laboratory tests to cover all of their bases. Many times numerous tests are ordered during the initial patient visit for the patient’s convenience so that they will not have to return for additional phlebotomy and testing. Another reason may that the physician perceives this may be their only chance to get this information.

In the September 15th blog, one study was cited that determined that between 7 and 15% of tests are repeated unnecessarily. Several reasons have been given to justify repeat testing.

  1. Confirm previous abnormal result
  2. Doubt accuracy or interpretation of previous result
  3. Monitor therapy
  4. Monitor disease progression
  5. Result not available
  6. Don’t trust result from outside institution
  7. Don’t take time to look up previous result
  8. Ratchet up likelihood of an almost certain diagnosis
  9. Reduce risk of malpractice claim
  10. Increase profitability

The first 5 reasons are usually justifiable, but the last 5 are not.

Duplicate orders on inpatients occur for many reasons. More than one physician is consulted to see a patient and hurried physicians often don’t check to see what tests have already been ordered. Many times panels with overlapping tests are ordered simultaneously. Examples include ordering a comprehensive metabolic panel, renal panel and liver panel. Sometimes physicians are unaware which tests are included in a panel and will order individual tests that already included in a panel. Any example is ordering hepatitis C antibody and a viral hepatitis panel. Sometimes orders are written for daily serial testing without a stop date. The availability of indwelling catheters for venous access in patients in the intensive care unit facilitates more frequent testing because the patient does not have to be stuck with a needle each time. Very few guidelines have been published pertaining to the appropriate interval for repeat testing in stable or unstable patients.

Another problem is that physicians may not be familiar with the indications and limitations of many of the newer, complex laboratory tests. It is estimated that as many as 4000 new tests will be introduced in the next 5 to 10 years. Only a hematologist would know when it is appropriate to order bcr/abl qualitative versus quantitative PCr or when bcr/abl p190 or p210 should be ordered. This problem is compounded when house staff search on Google to decide which tests to order.

Next week we will continue to explore other reasons for excessive testing.

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