When you have an otherwise healthy patient on whom you’re about to do surgery, what is your laboratory and imaging protocol? Do you do a full battery of labs? Do you order a standard complete blood count, comprehensive metabolic panel including bleeding labs, electrocardiogram, and chest radiograph? If you do, then I have an alternative paradigm for you.

When I started school, I was taught to order the full battery of labs and imaging on patients regardless of their health status.

“What if you missed the coagulation disorder?” I was asked.
“What if they have anemia, and you didn’t know it?”
“What if they have pneumonia or congestive heart failure?” I was admonished.

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In regard to pre-operative testing, the times, my friends, have changed.

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The Ridiculous

Those of you who might be prone to doing things the old way may argue preoperative battery testing provides medicolegal protection and screens for previously unknown (occult) disease, protecting both the patient and the doctor. The medicolegal argument is ridiculous. First, don’t practice in fear of being sued – it’s going to happen to you doctors, especially if you’re a surgeon. Don’t want to be sued? Stop practicing. Second, remember that as the ordering physician, you are required to treat or explain the lack of significance of every abnormal value that results from your testing. For podiatrists, that is likely to add a significant number of pointless referrals back to primary care physicians. I’m sure they’ll just love treating that otherwise normal but slightly low white blood cell count.

What Does the Research Say?

So then what does the research say about routine lab testing for preoperative evaluation?

The current more appropriate paradigm is to order only the labs and imaging based on the preoperative history and physical findings.

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Order only the labs and imaging based on the preoperative history and physical findings.

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There are volumes of research on this topic, so I’ll keep it brief and provide some evidence to support this paradigm. Here’s an example of how this method differs from the past. In the chart below, you’ll see a patient and the laboratory and imaging tests that would be ordered today versus the past.

• CBC
• Comprehensive Metabolic Panel
• TSH, T3, T4
• Pregnancy testing
• Chest radiograph

• TSH (thyroid function)
• Pregnancy testing.

Quite a difference, huh? The comprehensive metabolic panel includes 14 tests and the CBC includes seven values, which makes the difference 24 total tests more than necessary if using the prior method. Clearly, that’s going to be a major cost difference.

Cost vs Good Medical Care

Let’s not worry about the costs. Instead we’ll focus purely on the medical aspect. Since there are too many individual studies for us to discuss, let’s focus on systematic reviews and meta-analyses to cover the largest number of studies and highest quality research.

Balk and colleagues performed a systematic review in January 2014 of perioperative testing for cataract surgeries using sedation or general anesthesia. Their search found 57 quality comparative or cohort studies looking at mortality, perioperative events, patient satisfaction, and harms related to testing. They found routine testing with ECG, basic metabolic panel, or complete blood count did not affect surgery cancellations or total complications.¹

Want to order chest radiographs (CXR) for your asymptomatic patients? A Canadian systematic review (including 14 studies out of 513 that met criteria) found no association between CXR and decreased risk of perioperative morbidity and mortality in any age group (even those above 70 years-old). This review recommended only obtaining CXR for those patients with risk factors.²

Finally, a large-scale important United Kingdom systematic review from back in 1997 found the following results in otherwise healthy patients undergoing routine screening tests:³

These studies and many others demonstrate clearly that “routine” preoperative testing in otherwise healthy patients rarely changes treatment. Rely on your comprehensive history and physical examination to determine risk factors for your patients and rationally order testing in those patients when necessary.

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“Routine” preoperative testing in otherwise healthy patients rarely changes treatment

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