Essential Tips On ICD-10 And Wound Care Coding

Since ICD-10 has been fully implemented, podiatry practices are expected to provide the most accurate coding possible. This author offers a practical guide to diagnostic coding for ulcers and wounds, and pertinent insights on the nuances of adding fifth, sixth and seventh characters to your coding for ulcers and wounds.

The ICD-10 “grace period” that the Centers for Medicare and Medicaid Services (CMS) granted us ended on October 1, 2016. It is now more important than ever to ensure you are coding to the highest specificity and following all ICD-10 guidelines. While it is still unclear exactly how forgiving CMS was under this grace period, it is possible that some things that were working for you in the first year of ICD-10 may not continue be satisfactory with the grace period ending. Let us look specifically at proper diagnostic coding when it comes to wound care.

There have been disagreements, debates and even articles on the difference between what we consider a “wound” and what we consider an “ulcer.” Sometimes ICD-10 is almost like its own language and this is one of those situations.

Be aware that in ICD-10 language, a wound is something that occurred traumatically. All of the wound codes start with the letter S, placing them in Chapter 19 of the tabular index titled, “Injury, poisoning and certain other consequences of external causes.” The term ulcer refers to a break in the skin that fails to heal as it should and is typically more chronic in nature. While many of us may interchange the terms “ulcer” and “wound” as if they are synonyms, they are not synonyms when it comes to ICD-10 coding.

Deciding Which Type Of Ulcer To Code For

Once you have determined that you are dealing with an ulcer, you must determine the type of ulcer. That will get you started on finding the correct code. Options include diabetic foot ulcer, pressure ulcer, stasis ulcer or arterial ulcer. Diabetic foot ulcer coding begins with the L97- codes. Throughout this article, a “-” at the end of any code stem indicates that more characters are required to complete the code. Pressure ulcer codes begin with L89-. Stasis ulcer codes begin with I83- and codes for arterial ulcers are in the I70- section.

You may ask what to do when a diabetic foot ulcer is also pressure related. For example, a patient with diabetes, peripheral arterial disease (PAD) and neuropathy may develop an ulcer on the dorsal proximal interphalangeal joint of a contracted second toe. We could consider this ulcer an arterial ulcer, a neuropathic ulcer or a pressure ulcer. The National Pressure Ulcer Advisory Panel provided us with guidance in this area. For ICD-10 purposes, if there is an ulcer on the foot of a patient with diabetes, consider it a diabetic foot ulcer and code it using an L97- code. This is true even if arterial disease and/or pressure played a role in its development.

What You Should Know About ICD-10 Diabetic Foot Ulcer Codes

Looking more closely at the L97- code options for a diabetic foot ulcer, we see that we have to choose a fourth character of either “4” or “5” with the options being L97.4- (non-pressure chronic ulcer of heel and midfoot) or L97.5- (non-pressure chronic ulcer of other part of foot). The word “and” being in the description of the L97.4- codes brings us to an important ICD-10 lesson and another example of it sometimes being its own language. Whenever the word “and” appears in ICD-10 code descriptions, it actually means “and/or.” Therefore, if you use an L97.4- code, it does not necessarily imply that the patient has two ulcers, one involving the heel and one involving the midfoot.

We are still not done because once you have decided on a fourth character, a fifth character is required and the fifth character options are listed below.

Fifth character options for L97.4-:         
0 – Unspecified heel and midfoot          
1 – Right heel and midfoot          
2 – Left heel and midfoot                      

Fifth character options for L97.5-:
0 – Unspecified foot
1 – Right foot    
2 – Left foot

A sixth character is required for these codes as well and those options are listed below. You will notice the “unspecified” options in these listings. The “unspecified” options indicate to the payer that the documentation was incomplete and may lead to denial of payment. One should almost always avoid these unspecified options. With the fifth character laterality options, for example, a selection of “0” would indicate that the documentation specified neither left nor right.

Sixth character options for L97.4- and L97.5- codes:
1 – Limited to breakdown of skin
2 – With fat layer exposed
3 – With necrosis of muscle
4 – With necrosis of bone
9 – With unspecified severity

Notice in the sixth character options that “1” and “2” reference the depth of the ulcer, but “3” and “4” reference the depth of tissue that is necrotic. Just because an ulcer extends to a certain depth does not necessarily mean there is necrosis of tissue to that depth. Multiple organizations, including the American Podiatric Medical Association (APMA) and the Alliance of Wound Care Stakeholders, have submitted requests to the World Health Organization to make changes to the code descriptions that would address this inconsistency but no changes have occurred.

Our coding of a diabetic foot ulcer is not complete after choosing the fourth, fifth and sixth characters because the L97- codes require you to “Code first any associated underlying condition, such as diabetic ulcers (E08.621, E08.622, E09.621, E09.622, E10.621, E10.622, E11.621, E11.622, E13.621, E13.622).” Of these options, the most commonly used codes for diabetic foot ulcer are E10.621 (Type 1 diabetes mellitus with foot ulcer) and E11.621 (Type 2 diabetes mellitus with foot ulcer). “Code first” indicates that an additional code is required and you should list this first. Therefore, the order matters and E10.621 or E11.621 should precede the L97- code on the claim form.

For a patient with type 2 diabetes and a foot ulcer, we may still not be finished because under E11.621, we see the directions to “Use additional code to identify any insulin use (Z79.4)” and “Use additional code to identify oral hypoglycemic use (Z79.84). Therefore, we must also code Z79.4 if the patient uses insulin and Z79.84 if the patient is using oral hypoglycemic(s). Just as the order matters when we see “code first,” the order in which the codes are listed is important when one is instructed to “use additional code.” List the Z79.4 or Z79.84 code after E11.621. If this is not something you have been asking your patients with type 2 diabetes, you may be surprised how many are now taking insulin in comparison to 10 years ago.

Let’s go through the coding of a typical patient with type 2 diabetes who is taking daily insulin and has a chronic left lateral midfoot ulcer with necrosis of a muscle.When coding this patient encounter, you would start with L97.4- because this ulcer is on the midfoot. The fifth character would be “2” because it is the left foot and the sixth character would be “3” because there is necrosis of muscle. That leaves us with L97.423, which carries the instruction to code first E11.621 (type 2 diabetes mellitus with foot ulcer). Since this patient uses daily insulin, Z79.4 is necessary as well. Following the rules of “code first” and “use additional code,” the order of these codes would be E11.621 first, Z79.4 second and L97.423 last.

How To Code Pressure, Stasis And Arterial Ulcers

When coding a pressure ulcer, you look to the L89- codes and see the options listed below. Do not confuse “other” and “unspecified.” For reasons stated earlier, it is normally best to avoid unspecified codes but the use of “other” codes is fine when appropriate. Select the “other” option when the documentation does specify the location of the ulcer but there is not a more specific code that exists. An example of when this would be appropriate is a pressure ulcer on a toe. This would not fall under the codes for ankle or heel. Therefore, in this situation, consider the toe an “other” site.  

Pressure ulcer codes for podiatrists:
L89.51- Pressure ulcer of right ankle
L89.52- Pressure ulcer of left ankle
L89.61- Pressure ulcer of right heel
L89.62- Pressure ulcer of left heel
L89.89- Pressure ulcer of other site

All of these codes require a sixth character and those options are listed below. Use the “unstageable” option when you cannot determine the deepest layer of tissue involved because it is covered by slough and/or eschar, and it is not possible to stage the ulcer.

Sixth character options for pressure ulcers:
0 – Unstageable
1 – Stage 1
2 – Stage 2
3 – Stage 3
4 – Stage 4
9 – Unspecified stage

These codes are easier to complete than the diabetic foot ulcer codes as they do not have any “use additional code” instruction and the only “code first” instruction is to “code first any associated gangrene (I96).” If there is no associated gangrene, you do not need to include this.  

Stasis ulcer coding begins with either I83.0- (Varicose veins of lower extremities with ulcer) or I83.2- (Varicose veins of lower extremities with both ulcer and inflammation). Both of these require a fifth character and those options are listed below. Once again, attempt to avoid the unspecified option. If a patient has ulcers involving both the right and left extremities, list both codes as there is no bilateral option.

Fifth character options for I83.0- and I83.2-
0 – unspecified lower extremity
1 – right lower extremity
2 – left lower extremity

After selecting the fifth character, a sixth character is required for these codes and those options are listed below. When looking at the sixth character option of “4,” remember that “and” actually means “and/or.”  

Sixth character options for I83.0- and I83.2-:
1 – with ulcer of thigh
2 – with ulcer of calf
3 – with ulcer of ankle
4 – with ulcer of heel and midfoot
5 – with ulcer other part of foot
8 – with ulcer other part of lower leg
9 – with ulcer of unspecified site

All of these I83.0- and I83.2- codes carry the instruction to “use additional code to identify severity of ulcer (L97-).” This brings us back to the L97- codes I discussed above. Remember with the “use additional code” instruction, the L97- code will come after the I83- code when sequencing these codes.

The final ulcer option is arterial ulcers and one should code these starting either with I70.23- (Atherosclerosis of native arteries of right leg with ulceration) or I70.24- (Atherosclerosis of native arteries of left leg with ulceration). These codes require a sixth character and the options are the same as those listed for stasis ulcers listed immediately above. Also similar to coding for stasis ulcers, with these arterial ulcer codes, we must “use additional code to identify severity of ulcer (L97-).” If arterial ulcers are present on both right and left lower extremities, list both codes.

A Closer Look At Fifth, Sixth And Seventh Character Options For Wound Coding

Moving away from what ICD-10 considers ulcers and looking at wounds, we will look at codes for the pathologies most commonly encountered by podiatrists. The codes that start with S91.0- are the codes for open wounds of the ankle. Codes for open wounds of toes without damage to the nail begin with S91.1- and codes for open wounds of toes with nail damage start with S91.2-. For an open wound of the foot, codes start with S91.3-. These codes all require a fifth character and those fifth character options are listed below.

Fifth character options for S91- codes:
0 – Unspecified open wound
1 – Laceration without foreign body
2 – Laceration with foreign body
3 – Puncture wound without foreign body
4 – Puncture wound with foreign body
5 – Open bite

All of these codes also require a sixth character. The sixth character options for the S91.0- codes are “1” for right ankle and “2” for left ankle. The sixth character options for the S91.1- and S91.2- codes are more extensive and are listed below. The sixth character options for the S91.3- codes are “1” for right foot and “2” for left foot. When looking at these options, remember the recommendation to avoid the unspecified codes.

Sixth character options for S91.1- and S91.2- codes:
1 – right great toe
2 – left great toe
3 – unspecified great toe
4 – right lesser toe(s)
5 – left lesser toe(s)
6 – unspecified lesser toe(s)
9 – unspecified toe(s)

Finally, all of these S- codes listed above require a seventh character. This has been a point of confusion among many practitioners, mostly owing to the misleading descriptions of these characters. The seventh character options are A, D and S. Use “A” in the seventh character position if you provided active care during that visit. Use “D” as the seventh character if the care provided can be considered follow-up care. The selection of A or D has nothing to do with whether the patient has seen this doctor in the past or whether it is the first time the patient presented for this problem. The ICD-10 descriptions of A being for an “initial encounter” and D being for a “subsequent encounter” are misleading because they actually have nothing to do with whether it is an initial or subsequent encounter between that doctor and that patient as those terms are most frequently interpreted. Base the selection solely on what type of care you provided.

In Conclusion

Most podiatrists have reported an uneventful transition from ICD-9 to ICD-10. We don’t know how many, if any, problems doctors avoided with the “grace period” that we had from CMS. With the grace period ending on October 1, 2016, hopefully the guidance contained herein will ensure you code wound care perfectly.

Dr. Lehrman is on the American Podiatric Medical Association (APMA) Coding Committee, serves as an expert panelist on Codingline.com and is a Fellow of the American Academy of Podiatric Practice Management (AAPPM). Follow him on Twitter @DrLehrman .

References

1.     NDNQI Pressure Ulcers and Staging. Available at https://tinyurl.com/hsvb4xw .
2.     APMA Coding Resource Center. Available at https://www.apmacodingrc.org/home.asp .