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A44.0 ICD-10-CM Code: Systemic bartonellosis

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
1 inclusion term

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 867 — OTHER INFECTIOUS AND PARASITIC DISEASES DIAGNOSES WITH MCC (MDC 18)
  • MS-DRG 868 — OTHER INFECTIOUS AND PARASITIC DISEASES DIAGNOSES WITH CC (MDC 18)
  • MS-DRG 869 — OTHER INFECTIOUS AND PARASITIC DISEASES DIAGNOSES WITHOUT CC/MCC (MDC 18)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for A44.0 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Oroya fever

Code Overview

Systemic bartonellosis is a billable ICD-10-CM diagnosis code (A44.0).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (4)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Verify Before Coding

  • CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 56 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 867 (MDC 18), DRG 868 (MDC 18), DRG 869 (MDC 18).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):INF003 — Bacterial infections (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

A44.1 — Cutaneous and mucocutaneous bartonellosis, A44.8 — Other forms of bartonellosis, A44.9 — Bartonellosis, unspecified, A68.0 — Louse-borne relapsing fever, A68.1 — Tick-borne relapsing fever, A68.9 — Relapsing fever, unspecified, A69.20 — Lyme disease, unspecified, A69.21 — Meningitis due to Lyme disease, A69.22 — Other neurologic disorders in Lyme disease, A69.23 — Arthritis due to Lyme disease, A69.29 — Other conditions associated with Lyme disease, A75.0 — Epidemic louse-borne typhus fever due to Rickettsia prowazekii, A75.1 — Recrudescent typhus [Brill's disease], A75.2 — Typhus fever due to Rickettsia typhi, A75.3 — Typhus fever due to Rickettsia tsutsugamushi, A75.9 — Typhus fever, unspecified, A77.0 — Spotted fever due to Rickettsia rickettsii, A77.1 — Spotted fever due to Rickettsia conorii, A77.2 — Spotted fever due to Rickettsia siberica, A77.3 — Spotted fever due to Rickettsia australis, +35 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Bacterial infections).

+399 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Fever”; these codes share that main term but sit in a different category of the Tabular List.

A23.9 — Brucellosis, unspecified (Malta), A25.0 — Spirillosis (spirillary), A25.1 — Streptobacillosis (Haverhill), A25.9 — Rat-bite fever, unspecified (rat-bite), A27.0 — Leptospirosis icterohemorrhagica (icterohemorrhagic), A27.89 — Other forms of leptospirosis (seven day), A27.9 — Leptospirosis, unspecified (mud), A28.1 — Cat-scratch disease (cat-scratch), A38.9 — Scarlet fever, uncomplicated (scarlet), A39.0 — Meningococcal meningitis (petechial), A48.2 — Nonpneumonic Legionnaires' disease [Pontiac fever] (Pontiac), A48.4 — Brazilian purpuric fever (Brazilian purpuric), A68.0 — Louse-borne relapsing fever (relapsing, Obermeyer's), A68.1 — Tick-borne relapsing fever (mianeh), A68.9 — Relapsing fever, unspecified (relapsing), A70 — Chlamydia psittaci infections (parrot), A75.0 — Epidemic louse-borne typhus fever due to Rickettsia prowazekii (famine), A75.2 — Typhus fever due to Rickettsia typhi (Mexican), A75.3 — Typhus fever due to Rickettsia tsutsugamushi (kedani), A75.9 — Typhus fever, unspecified (Canton), +109 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

HIV Screening Test

Contextual Map

Every relationship of A44.0 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 18 — Infectious and Parasitic Diseases, Systemic or Unspecified Sites[MDC crossing]: “Infectious and Parasitic Diseases, Systemic or Unspecified Sites — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 1 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

  • Bartonellosis, systemic[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Carrion's disease[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor), Bartonella[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor), Oroya[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "A44.0 — Systemic bartonellosis." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/a44.0-systemic-bartonellosis

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Systemic bartonellosis

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to A44.0 in its code family, with their registry titles.

View all codes in the A44 family