ICD-10 Diagnosis Codes Decide Whether or Not Medicare Will Pay

Woman speaking with her doctor and looking at paperwork after a bone scan
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It takes years of education and training to teach doctors the skills needed to evaluate a patient, make a diagnosis, and treat that person according to the standard of care. In 2015, a new layer of complexity was added that affects whether or not your insurance plan will pay for your care — a change in diagnosis codes.

How Medical Billing Works

You could take a course to understand the intricacies of medical billing, but what you really need to know are the aspects of billing that affect you on a personal level.

In simple terms, your doctor evaluates you, picks a diagnosis code to match your condition, and chooses a billing code based on the complexity of your visit. Any tests ordered must also be linked to the diagnosis code. This information is then directed to your insurance company, Medicare included, so your doctor gets paid for his service.

If your doctor does not pick the right diagnosis code, it is possible your insurance plan will not pay for the care you received. That leaves you paying not only a copay or coinsurance for the test or visit but the full dollar amount.

The Change from ICD-9 to ICD-10 Codes

The International Classification of Diseases is a toolbox of diagnosis. In its 10th edition (ICD-10) since 1990, this list of diagnoses is used worldwide to track disease and mortality rates. Standardizing diagnosis codes also improves the ability to track health initiatives, monitor health trends, and respond to health threats.

The United States, however, was slow to adopt the most recent codes and did not transition from ICD-9 to ICD-10 until October 2015.

There are more diagnosis codes than you can imagine. The number of possible codes your healthcare provider must choose from exponentially increased in October 2015. There are 155,000 codes available in the 2015 version of ICD-10 as compared to the 17,000 codes in ICD-9.

For 2018, there will be 363 new codes, 142 inactivated codes, and 226 revised codes.

This increased specificity made it harder for doctors to find the codes they need to get insurance to pay. A pilot study by the Healthcare Information Management Systems Society suggests that only 63 percent of ICD-10 coding may be accurate. More billing errors could lead to you paying more than your fair share.

Choosing the Right Code

To get an idea of the complexity of ICD-10, look at common upper respiratory complaints. Allergic rhinitis (a runny nose from allergies) has at least six different codes from which to choose, pneumonia 20 codes, asthma 15 codes, influenza 5 codes, sinusitis 21 codes, and sore throat 7 codes. Those are the easy ones.

Complicated conditions like hypertension have many layers to the diagnosis that show how the condition relates to heart disease, kidney disease, pregnancy, and more. Diabetes has even more codes. There are even three codes for being struck by a falling object on a sailboat! You can amuse yourself and search for codes on the Centers for Medicare and Medicaid (CMS) website.

Example: Medicare only pays for bone density screening for osteoporosis if certain ICD-10 codes are used. Medicare will deny coverage for ICD-10 code M85.80, "other specified disorders of bone density and structure, unspecified site", but will approve reimbursement for M85.81x-M85.89x, codes that specify the location (ankle, foot, forearm, hand, lower leg, shoulder, thigh, upper arm, or multiple sites) and laterality (left or right) of the bone disorder, i.e., M85.822, "other specified disorders of bone density and structure, left upper arm."

This is an oversimplification as there many other codes that will cover for bone density screening. However, it is easy to see how a single digit could decide who pays for your care, you or your insurer.

Appealing Your Case

After the transition to ICD-10 in 2015, the Centers for Medicare and Medicaid Services (CMS) allowed for a one year grace period for billing purposes. Simply put, CMS granted doctors leniency for 12 months. As long as doctors coded in the right category for a disease, even if it was not the preferred code, they would not be penalized by CMS and your care should be covered. That is no longer the case.

If at any time you receive a bill that you do not think you should be required to pay, contact your doctor's office. It is possible they have used the wrong ICD-10 code. Your doctor may be able to change the diagnosis code to one that gives you the insurance coverage you need.

A Word From Verywell

Doctors are better versed in medical care than medical billing. With more than 155,000 ICD-10 codes available, it is possible your doctor could choose the wrong one. If Medicare denies payment for services because of a coding error, you are left to pay out of pocket. Know your rights. Reach out to your healthcare provider's billing office if you find any discrepancies in your billing.

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Article Sources

  • 2018 ICD-10 CM and GEMs. Centers for Medicare and Medicaid Services website.

  • Bone Mass Measurement ICD-10 Covered Services Updated. American College of Radiology website.

  • Herman, B. Only 63% of ICD-10 Documentation Accurately Coded. Becker's Hospital CFO Report website.

  • ICD-10 Code Look Up. Centers for Medicare and Medicaid Services website.

  • International Classification of Diseases (ICD). World Health Organization website.