BKS Partners Workers' Compensation Blog

You Down With MCC?

Posted by Tim Liberty on Jan 30, 2017 3:47:52 PM
Tim Liberty

Major Contributing Cause. Have you heard of this term before? You may have or its acronym, MCC, tossed around at a claims review, but claims people can be guilty of over-acronymizing and spewing jargon around non-claims folks. Although you may have heard of MCC you may not have a solid grasp on its meaning and how it should be used in Florida work comp claims.


MCC means the cause which is more than 50% responsible for the injury as compared to all other causes combined. Those other causes would be pre-existing or subsequent injuries and conditions. The determination on the percentage would be opined by the medical provider. Prior to 1994 when the MCC statute was enacted, causal connection would be established by showing that an accident played some minor role in causing the worker’s symptoms. This change was a huge cost-saver for employers as they had a new tool to mitigate from having to pay for medical treatment for pre-existing injuries and conditions.

You have probably seen a DWC25 form if you've had to deal with work comp claims. They are a required form that is produced by a doctor after each appointment that displays a work status, diagnosis, treatment plan, etc. On it is a section (box 13) for the doctor to check whether the injury is the major contributing cause for the need for treatment. I often see this box left blank or filled out incorrectly when there is admitted pre-existing conditions. One strategy to ensure the MCC is addressed is to have the insurer send a letter to the doctor explaining MCC and asking for their opinion broken down into percentages. Often it helps to have the letter delivered by a nurse familiar with MCC. This is especially important for Florida claims where the injured worker has since moved to another state, and the doctor is not familiar with Florida law. If there is still doubt, defense attorneys can set up a call or meeting with the doctor to better explain the law. This is usually a good strategy as that doctor may be deposed by the plaintiff counsel, and a conference will ensure they have the best understanding of the law so they can give an accurate opinion.

If the authorized treating provider opines that the MCC is 50% or below, the claim would be denied. That doesn’t necessarily leave the injured worker high and dry. When a denial is issued they can then treat under their health insurance and will have the opportunity to select their doctors, which they cannot do inside of Florida work comp. They also have the option of pursuing an independent medical examination to contest the opinion.

It is important to understand MCC because in many cases adjusters will glaze over a DWC25 and not question the doctor when there are errors. It takes some time and energy to dig deeper into an MCC opinion, and for many adjusters carrying high caseloads, they don’t get around to it. This lack of aggression can cause employers to pay higher claims costs which will equal premiums. Don’t let your adjuster be passive when it comes to MCC.


The BKS Blog was written to keep you informed and help you learn about the changing landscape of workers' compensation insurance. These articles are written for employers who are researching additional information about changes, or looking to change their insurance partner.

With this blog you'll:

  • Learn tips on saving money within your workers' comp program
  • Stay up to date with industry changes in workers' compensation insurance
  • Discuss strategies and best practices to ensure the lowest cost of risk

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