2027 ICD-10-CM Diagnosis Code A01.05Typhoid osteomyelitis
ICD-10-CM Codes›A00–B99›A00-A09›A01
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 92
- Not Chronic
A01.05 is a billable ICD-10-CM diagnosis code for typhoid osteomyelitis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 867 through 869. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 11 closely related codes. Coders also document this condition as bacterial osteomyelitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Osteomyelitis.
For Medicare Advantage risk adjustment, A01.05 maps to CMS-HCC Category 92 (Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis) under the V28 model, adding a risk factor of about 0.479 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
A01.05 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Bacterial osteomyelitis
- Osteomyelitis caused by Salmonella enterica enterica serovar Typhi
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to A01.05: its own notes plus those printed at Chapter 1. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- diseases generally recognized as communicable or transmissible
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- carrier or suspected carrier of infectious disease (Z22.-)
- certain localized infections - see body system-related chapters
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
- infectious and parasitic diseases specific to the perinatal period (P35-P39)
- influenza and other acute respiratory infections (J00-J22)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify resistance to antimicrobial drugs (Z16.-)
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name A01.05, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming A01.05: they are not reported together with it, unless the two conditions are unrelated.
- M49 Spondylopathies in diseases classified elsewheretyphoid fever spondylitis (A01.05)
Excludes2 2
These codes carry an Excludes2 note naming A01.05: its condition is not part of those codes, and both may be reported when the patient has both.
- Block P35-P39 Infections specific to the perinatal period
- P37 Other congenital infectious and parasitic diseases
Code First 1
These codes say to code first a condition named in the note, and A01.05 is one of the conditions named.
- M49 Spondylopathies in diseases classified elsewhere
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Osteomyelitis (general) (infective) (localized) (neonatal) (purulent) (septic) (staphylococcal) (streptococcal) (suppurative) (with periostitis) M86.9
typhoid A01.05
Spondylitis (chronic) See Also: Spondylopathy, inflammatory;
typhosa A01.05
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Typhoid Fever
an acute systemic febrile infection caused by salmonella typhi, a serotype of salmonella enterica.
Patient EducationClinical
Bone Infections
Like other parts of the body, bones can get infected. The infections are usually bacterial, but can also be fungal. They may spread to the bone from nearby skin or muscles, or from another part of the body through the bloodstream.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert A01.05 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About A01.05Overview
What is the ICD-10 code for typhoid osteomyelitis?
The ICD-10-CM code for typhoid osteomyelitis is A01.05 (sometimes written as A0105). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is A01.05 (Typhoid fever) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report typhoid osteomyelitis on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does A01.05 group to?
When typhoid osteomyelitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 867, 869, 868, with relative weights from 0.6784 to 2.1855 depending on complications. Higher weights mean higher Medicare reimbursement.
Is A01.05 a CC or MCC?
CMS lists A01.05 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 11 closely related codes in its exclusion list.
What is the ICD-9 equivalent of A01.05?
Under the General Equivalence Mappings, typhoid osteomyelitis converts to ICD-9-CM 002.0 (typhoid fever). The mapping is approximate, so confirm the match fits the documentation.
What HCC is A01.05?
A01.05 (typhoid osteomyelitis) maps to CMS-HCC Category 92 (Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis), commonly written as HCC 92, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 39 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.
Does A01.05 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, A01.05 adds a risk adjustment factor of about 0.479 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.471 to 0.632 depending on the payment segment). HCC 92 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 92 category page.
