Can we cut back on lab testing?

A 64-year-old man presented to my office with a history of a 0.4 mm thickness melanoma having been excised from his back in 2014. He subsequently saw his primary care provider, who decided to order a PET scan just to be sure that “everything was OK.” $7,500 later, the patient was relieved to be told that the scan was completely normal.

What is wrong with this scenario? The patient is relieved to find that his melanoma has not disseminated. The ordering physician is happy to give him the good news and is assured in his own mind that he has done everything possible to manage the disease. 

READ: Isotretinoin - Time to reconsider blood tests?

Furthermore, if the patient should develop late metastases, the physician has built a firewall around himself against possible malpractice litigation. In fact, there is recent published data to support the notion that more laboratory testing does lead to fewer malpractice claims.¹ The authors report that practitioners in acute care hospitals in Florida who used more resources in patient management had fewer malpractice claims filed against them.

I suspect that most dermatologists in this country would not order a routine PET scan for this patient in spite of the positive feedback they might get from doing so, simply because there is no data to support the survival benefit of PET scans in those with a thin melanoma, and ordering such a scan fails the “reasonableness test” of cost-to-benefit analysis.

Organized medicine is beginning to take an active role in assisting physicians in deciding the value of certain laboratory examinations. A good example of this is the PSA test for prostate cancer, which is no longer being recommended routinely based on extensive clinical data that shows the test has poor predictive value. An interesting recent study in the allergy literature² concludes that no diagnostic testing may be necessary or useful in patients with chronic urticaria after a medical history and physical examination fail to direct one to an underlying cause of the eruption.

We utilize numerous medications in dermatology where potentially severe side effects can occur and can be detected by laboratory analysis. No one would argue against a person about to be placed on methotrexate having a baseline complete blood count, liver and renal function testing and screening for active hepatitis infection, with routine follow-up testing for the duration of the treatment period. We know that tuberculosis screening is important in those about to be started on biologic agents. Patients in my part of the country also need tests for coccidioidomycosis because it is endemic and can be a severe problem in immunocompromised individuals. Those on cyclosporine require frequent monitoring of blood pressure and renal function and occasional testing for low magnesium. However, many commonly prescribed drugs rarely cause problems but have acquired the reputation of potentially toxic agents, which require close laboratory monitoring. 

My view on where derms over test

Although many would disagree with the list below, these are, in my view, the major over-tested medications that we use:

Isotretinoin can elevate serum cholesterol and triglyceride levels. However, if these abnormalities do not appear in the first month of therapy, there is little or no chance that they will appear later in the course of treatment. Thus, there is no reason for monthly lipid profiles after the first month. Isotretinoin was developed, in part, as a safer alternative to vitamin A, a known liver toxin. It is only a rare cause of clinically relevant liver injury, and testing for this possibility is largely a waste of time and money, especially after the first two months.

Biologic agents do suppress the immune system with potential serious consequences. However, there is no credible reason to get routine chemistry profiles as part of a baseline or follow-up examination because, with rare exceptions, there is no test result that would force one to either alter the dose or discontinue the medication altogether.

Metastatic melanoma can involve almost any organ. Vigilance is useful. However, routine laboratory monitoring with chest radiographs and alkaline phosphatase determinations are of no value in the early detection of metastatic disease.

Some would argue that there is no harm in getting extra laboratory tests because some abnormality may be detected that could lead to early treatment. Others would more cynically suggest that the more laboratory tests that become a part of the medical record, the more competent the treating physician will appear if he is ever sued for medical malpractice. However, there is a substantial price to pay for all of these extraneous tests. Obviously, they increase the costs of healthcare substantially. Of equal importance is the simple act of getting laboratory tests can be extremely stressful for many people. We often check off a box on the order form and then forget about it. However, patients can lose sleep over the possible bad news that awaits them from the next phone call from the doctor’s office. In addition, screening tests often produce what amount to false positive abnormalities, which are sometimes difficult to dismiss outright without additional attention to the possible medical issues associated with these abnormal results.

Dermatology patients are largely spared from the over-testing seen in other specialties. In order to keep this good track record intact, we must continue to keep the patient’s best interest in mind when contemplating laboratory evaluations. After all, it is all about providing optimal care to our patients, which may include doing less rather than more. 

References

1.
Jena AB, Schoemaker L, Bhattacharya J, Seabury SA. Physician spending and subsequent risk of malpractice claims: observational study. British Medical Journal 2015;351:h5516

2.
Bernstein JA, Lang DM, Khan DA et al. The diagnosis and management of acute and chronic urticarial: 2014 update. J. Clinical Allergy and Immunology 133:1270, 2014.