M35.81

ICD-10-CM Official Guidelines for Coding and Reporting, quoted in full. Published by CMS and NCHS; in the public domain.

I.C.1.g.1.h.i Personal history of COVID-19 names this code p.31

For patients with a history of COVID-19, assign code Z86.16, Personal history of COVID-19. (j) Follow-up visits after COVID-19 infection has resolved For individuals who previously had COVID-19, without residual symptom(s) or condition(s), and are being seen for follow-up evaluation, and COVID-19 test results are negative, assign codes Z09, Encounter for follow-up examination after completed treatment for conditions other than malignant neoplasm, and Z86.16, Personal history of COVID-19. For follow-up visits for individuals with symptom(s) or condition(s) related to a previous COVID-19 infection, see guideline I.C.1.g.1.m. See Section I.C.21.c.8, Factors influencing health states and contact with health services, Follow-up (k) Encounter for antibody testing For an encounter for antibody testing that is not being performed to confirm a current COVID-19 infection, nor is a follow-up test after resolution of COVID-19, assign Z01.84, Encounter for antibody response examination. Follow the applicable guidelines above if the individual is being tested to confirm a current COVID-19 infection. For follow-up testing after a COVID-19 infection, see guideline I.C.1.g.1.j. (l) Multisystem Inflammatory Syndrome For individuals with multisystem inflammatory syndrome (MIS) and COVID-19, assign code U07.1, COVID-19, as the principal/first-listed diagnosis and assign code M35.81, Multisystem inflammatory syndrome, as an additional diagnosis. If an individual with a history of COVID-19 develops MIS, assign codes M35.81, Multisystem inflammatory syndrome, and U09.9, Post COVID-19 condition, unspecified. If an individual with a known or suspected exposure to COVID- 19, and no current COVID-19 infection or history of COVID-19, develops MIS, assign codes M35.81, Multisystem inflammatory syndrome, and Z20.822, Contact with and (suspected) exposure to COVID-19. Additional codes should be assigned for any associated complications of MIS. (m) Post COVID-19 Condition For sequela of COVID-19, or associated symptoms or conditions that develop following a previous COVID-19 infection, assign a code(s) for the specific symptom(s) or condition(s) related to the previous COVID-19 infection, if known, and code U09.9, Post COVID-19 condition, unspecified. Code U09.9 should not be assigned for manifestations of an active (current) COVID-19 infection. If a patient has a condition(s) associated with a previous COVID-19 infection and develops a new active (current) COVID-19 infection, code U09.9 may be assigned in conjunction with code U07.1, COVID-19, to identify that the patient also has a condition(s) associated with a previous COVID-19 infection. Code(s) for the specific condition(s) associated with the previous COVID-19 infection and code(s) for manifestation(s) of the new active (current) COVID-19 infection should also be assigned. (n) Underimmunization for COVID-19 Status Code Z28.310, Unvaccinated for COVID-19, may be assigned when the patient has not received a COVID-19 vaccine of any type. Code Z28.311, Partially vaccinated for COVID-19, may be assigned when the patient has been partially vaccinated for COVID-19 as per the recommendations of the Centers for Disease Control and Prevention (CDC) in place at the time of the encounter. For information, visit the CDC’s website https://www.cdc.gov/covidschedule. See Section I.B.14. for underimmunization documentation by clinicians other than patient's provider.

I.C.13 Chapter 13: Diseases of the Musculoskeletal System and Connective names this code p.60

Tissue (M00-M99)

I.C.13.a Site and laterality chapter guidance p.60

Most of the codes within Chapter 13 have site and laterality designations. The site represents the bone, joint or the muscle involved.

I.C.13.a.1 Bone versus joint chapter guidance p.60

For certain conditions, the bone may be affected at the upper or lower end, (e.g., avascular necrosis of bone, M87, Osteoporosis, M80, M81). Though the portion of the bone affected may be at the joint, the site designation will be the bone, not the joint.

I.C.13.a.2 Multiple sites chapter guidance p.61

Codes describing specified sites are assigned individually by site when documented. When the specified site(s) are not documented, assign the appropriate code for “multiple sites.”

I.C.13.b Acute traumatic versus chronic or recurrent musculoskeletal chapter guidance p.61

conditions Many musculoskeletal conditions are a result of previous injury or trauma to a site, or are recurrent conditions. Bone, joint or muscle conditions that are the result of a healed injury are usually found in chapter 13. Recurrent bone, joint or muscle conditions are also usually found in chapter 13. Any current, acute injury should be coded to the appropriate injury code from chapter 19. Chronic or recurrent conditions should generally be coded with a code from chapter 13. If it is difficult to determine from the documentation in the record which code is best to describe a condition, query the provider.

I.C.13.c Coding of Pathologic Fractures chapter guidance p.61

7 character A is for use as long as the patient is receiving active treatment for the fracture. While the patient may be seen by a new or different provider over the course of treatment for a pathological fracture, assignment of the 7 character is based on whether the patient is undergoing active treatment and not whether the provider is seeing the patient for the first time. 7th character D is to be used for encounters after the patient has completed active treatment for the fracture and is receiving routine care for the fracture during the healing or recovery phase. The other 7 characters, listed under each subcategory in the Tabular List, are to be used for subsequent encounters for treatment of problems associated with the healing, such as malunions, nonunions, and sequelae. Care for complications of surgical treatment for fracture repairs during the healing or recovery phase should be coded with the appropriate complication codes. See Section I.C.19. Coding of traumatic fractures.

I.C.13.d Osteoporosis chapter guidance p.61

Osteoporosis is a systemic condition, meaning that all bones of the musculoskeletal system are affected. Therefore, site is not a component of the codes under category M81, Osteoporosis without current pathological fracture. The site codes under category M80, Osteoporosis with current pathological fracture, identify the site of the fracture, not the osteoporosis.

I.C.13.d.1 Osteoporosis without pathological fracture chapter guidance p.62

Category M81, Osteoporosis without current pathological fracture, is for use for patients with osteoporosis who do not currently have a pathologic fracture due to the osteoporosis, even if they have had a fracture in the past. For patients with a history of osteoporosis fractures, status code Z87.310, Personal history of (healed) osteoporosis fracture, should follow the code from M81.

I.C.13.d.2 Osteoporosis with current pathological fracture chapter guidance p.62

Category M80, Osteoporosis with current pathological fracture, is for patients who have a current pathologic fracture at the time of an encounter. The codes under M80 identify the site of the fracture. A code from category M80, not a traumatic fracture code, should be used for any patient with known osteoporosis who suffers a fracture, even if the patient had a minor fall or trauma, if that fall or trauma would not usually break a normal, healthy bone.

I.C.13.e Multisystem Inflammatory Syndrome chapter guidance p.62

See Section I.C.1.g.1.l. for Multisystem Inflammatory Syndrome

Risk adjustment

This code