The AMA Guides to the Evaluation of Permanent Impairment and the California Permanent Disability Rating Schedule feature subtle differences in rating instructions that can cause confusion about how to rate permanent disability.

Tim Mussack

Our ratings department sometimes receives questions about certain instructions in the AMA Guides that are not followed in the California workers’ compensation system.

AMA Guides vs. California PDRS

The AMA Guides include instructions for calculating regional impairment for the spine, upper extremities and lower extremities, which are not always applicable for California ratings.

It’s important to note that the AMA Guides are not jurisdictionally specific and instead were created to guide evaluations for numerous state and federal systems. There are jurisdictions that offer disability values for regions of the body, such as the Department of Labor, for example.

The Department of Labor’s PD rating schedule says that an arm/upper extremity is worth 312 weeks of compensation. With that in mind, here is an example: A 50% upper extremity impairment rating provides half of the value for an arm. So if a full arm is worth 312 weeks, then half of an arm is worth 156 weeks.

This differs from the California workers’ compensation system, which uses a different permanent disability rating schedule. In the California workers’ compensation system, practitioners don’t usually don’t rate an arm; we rate a shoulder, an elbow, a wrist, etc. This is explained in further detail below.

California's PD rating system

The 2005 California Permanent Disability Rating Schedule was created after the Legislature agreed to require the use of the AMA Guides' fifth edition to determine impairment in California.

Section 1 of the 2005 PDRS is named “Introduction and Instructions,” and it addresses the PD rating issues that are unique to California. Section 1 includes instructions regarding our state-specific rating adjustments for WPI increase (FEC or 1.4 "adjustment factor"), occupation and age adjustments. It also includes instructions for combining and rating pain and for rating psych injuries using the GAF.

Thus, it’s very important to remember that when faced with any seemingly conflicting instructions, use the California PDRS instructions for addressing permanent disability.

For example, pages 1-11 of the California PDRS offer some specific instructions that differ from the AMA Guides. Those pages specifically state that “except as specified below, all impairments” are adjusted and then combined. It goes on to list impairment numbers to address different parts of the body and notes it.

Going back to our example, this is where things differ from the Department of Labor’s rating schedule. In California, we would rate different parts of the upper extremity (ex: shoulder, elbow, wrist) and combine them, instead of rating “an arm” as the Department of Labor would have us do.

Other examples

When it comes to upper and lower extremities, the AMA Guides and the California PDRS differ again.

For example, when rating lumbar impairment using the range-of-motion method, the AMA Guides and the PDRS differ when it comes to when one combines different impairment values.

When rating the spine using the range-of-motion method:

• Spinal disorder (table 15-7) and motion impairment are combined and rated together using 15.03.02.xx (for the lumbar spine).
• Any residual lower extremity sensory deficits are combined and rated using 15.03.02.05. Residual lower extremity motor deficits are combined and rated using 15.03.02.06.

There are multiple levels when rating impairment of extremities, which are:

1. Extremity impairment — upper extremity impairment (UEI) and/or lower extremity impairment (LEI).
2. Whole-person impairment — one combines UEI or LEI and transforms it into whole-person impairment (WPI).
3. PD rating level — one combines WPIs and transforms them into a PD rating.

So when one looks at these different levels, one should note that the AMA Guides instruct to combine some values at the whole-person impairment level.

That differs from the CA PDRS, which calls for the combination of extremity impairments “involving a single part of an extremity” at the extremity impairment level (aka the first level).

In other words, the California Permanent Disability Rating Schedule is different in the respect that specific impairment numbers are a guide as to what level we should rate and what impairments we should rate.

A good example is when one has to rate for what a layman would call “a wrist.”

The California PDRS has separate impairment numbers for peripheral neuropathy, a specific number for carpal tunnel and a specific number for wrist range of motion.

We would normally consider each separate body part/organ system assessment as a separate rating. Wrist (elbow, shoulder) "other" would include ROM and any appropriate "other disorder" that is not a peripheral nerve disorder.

California also varies with the Almaraz/Guzman rating doctrine, which allows physicians to use a rating by analogy in rare cases where the medical expert believes the PD rating is wholly inequitable. When applying Almaraz/Guzman in a rating, those must use .99 at the end of the impairment number, according to instructions from California’s Disability Evaluation Unit.

For example, if one were to:

• Rate headaches using Almaraz/Guzman, it would look like 13.01.00.99, according to the DEU.
• Use Alamaraz/Guzman rate elbow “by analogy” with Table 16-18, it would use impairment number: 16.03.02.99.

Summary

The AMA Guides are not jurisdictionally specific. They include some instructions for calculating regional impairment for the spine, upper extremities and lower extremities that differ from the California PDRS.

As such, when it appears there is a conflict between rating systems, we strongly recommend the use of the California PDRS for workers’ compensation claims.

Tim Mussack leads Bradford & Barthel’s AMA Guides and ratings department. This entry from Bradford & Barthel's blog appears with permission.