I recently spoke to a class of undergraduates about the benefits, harms and politics of screening smokers for lung cancer using low-dose CT scans. Afterwards, a student asked how I felt about the Affordable Care Act’s requirement that Medicare and private insurers cover U.S. Preventive Services Task Force “A” and “B” recommended screening tests and other preventive services without co-payments or deductibles, making them free at the point of care.

I admitted that I have mixed feelings. On one hand, some studies have found that even small out-of-pocket payments make patients less likely to receive recommended health screenings or counseling. On the other, it isn’t clear why this particular set of services for healthy people (which include contraceptives classified as “pregnancy prevention”) deserve to be valued more than medical interventions for people who actually suffer from chronic illnesses. The chance that a 50 year-old woman at average risk for breast cancer will have her life extended by a screening mammogram is around 1 in 1000; the chance that a 50 year-old woman with diabetes and high blood pressure will have her life extended by taking fitness classes and anti-hypertensive drugs is around 1 in 20. The healthy person receives a service for free; the ill person does not. And, as I wrote in a blog post shortly after the 2012 presidential election, that mammogram isn’t really free:

Thanks to the ACA / Congressional Democrats / President Obama, a typical political ad will say, women can now get free mammograms, Pap smears, cholesterol tests, and birth control pills! Isn’t that great? This kind of ad is misleading because none of the preventive health services defined by the bill have suddenly become free. In fact, some cost hundreds or even thousands of dollars. Instead, the costs of these services have just been shifted – into higher insurance premiums, on to an employer, or to the federal government (and therefore the individual taxpayer or an international investor that holds some portion of the U.S.’s $16 trillion national debt).

A perceptive commentary in this week’s JAMA by Drs. Joann Elmore and Barry Kramer offered more reasons to doubt the wisdom of mandating that marginally beneficial preventive services be provided for free:

With the goal of improving access to preventive services and medical screening, the ACA offers free screening mammography to women. However, women often pay for the consequences of screening, even if the screening examination is free. Women bear not only financial charges but also important human costs. Screening mammography can trigger recalls for more testing, biopsies, mastectomies, radiation, systemic therapy, days off work, and debt related to health care costs. These byproducts of screening can lead to adverse financial consequences and personal harm.

Two years ago, I bought a color printer for under $50 (practically free!) for my home office. It printed pages excruciatingly slowly, had a tendency to jam and leak toner, and sets of replacement cartridges came to $75 every other month. Several weeks ago it quit printing any documents that required black ink. After spending hours trying unsuccessfully to troubleshoot the problem, I paid five times as much for a new printer, and so far it’s worked like a dream.

Do I provide mammograms and other USPSTF-recommended “free” screening tests to my patients? Of course I do. But I also caution them not to be deceived by the sticker prices for these services and exaggerated claims about their benefits, and to consider more than upfront costs in determining personal health values, as they would in making decisions about the value of any other service that costs money.

Kenneth Lin is a family physician who blogs at Common Sense Family Doctor.