SEPTEMBER 24, 2012
We are ordering too many preop tests

As predictable as the leaves falling this time of year, another paper on the subject of unnecessary preoperative laboratory testing has appeared.

A group from the University of Texas Medical Branch looked at more than 73,000 elective hernia repairs in the National Surgical Quality Improvement Project (NSQIP) database. Almost 2/3 of the patients had preoperative laboratory tests. Of that group, 58.6% had a CBC, 53.5% had chemistries, 23.7% had liver function studies, 18.7% had coagulation studies and 9.9% had all of the above. Even 54% of patients with no co-morbidities had at least one test.

An abnormal test was found in more than 60% of those tested, of the 7200 patients who had lab tests done on the day of surgery, 61.6% had at least one abnormal test including 23% with a coagulation abnormality, 41% with a chemical abnormality and 33% with an LFT abnormality. Despite these results, the scheduled surgery was done.

Tests did not predict complications in patients without co-morbidities. Obtaining a test (not necessarily an abnormal result) was associated with a higher risk of major complications (0.4% versus 0.2% p < 0.0001) but not wound complications. However, abnormal results did not predict complications.

The authors of the paper recommended that surgical societies establish guidelines for preop testing.

Hernia patients, particularly those without comorbidities, are similar to normal people. Obtaining lab studies on these patients is analogous to obtaining labs on the next 100 people who walk past the hospital. Few abnormal results will be found, and most of them will be false positives.

This fact has been known for at least 30 years, yet surgeons, who as shown by previous studies order 80% of preop tests, still continue to order them. Some question whether anesthesiologists insist on having the tests done. Is it defensive medicine? Force of habit?

When I was a department chairman and this subject came up for discussion, at least one person always said, "But if you miss one patient with (you fill in the blank), you will get sued." That type of comment is very difficult to refute because there is a grain of truth to it.

As far as I can tell, "I was following evidence-based guidelines" is not a foolproof defense against a malpractice suit. While there have been some attempts to legislate that  following evidence-based guidelines should "immunize" doctors against malpractice suits, to my knowledge, no such laws exist. In 2004, an article in the AMA’s Virtual Mentor journal discusses this point very well as does a more recent paper from the Journal of Law, Medicine & Ethics.

What then is a practicing physician to do? That unnecessary pre-op testing occurs has been understood for many years. The paper points out that the estimated cost of preoperative testing is anywhere from $3 billion to $18 billion. Several esteemed associations and societies have established guidelines which are not followed.

Meanwhile, extensive preoperative testing of ambulatory patients continues at the discretion of the surgeon, anesthesiologist and probably the patient’s primary care doctor too. And the tab mounts.

Skeptical Scalpel is a practicing surgeon and was a surgical department chairman and residency program director for many years. He is board-certified in general surgery and a surgical sub-specialty and has re-certified in both several times. For the last two years, he has been blogging at and tweeting as @SkepticScalpel. His blog has had more than 260,000 page views, and he has over 3500 followers on Twitter.



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