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HCC 6: Opportunistic Infections

HCC 6, Opportunistic Infections, is one of the 115 payment categories in the CMS-HCC V28 model. 37 ICD-10-CM codes map to it in the payment year 2027 mapping, and a documented diagnosis in the category adds a relative factor of 0.381 to the risk score of a community, non-dual, aged beneficiary (0.763 disabled, 0.728 institutional). It sits at the top of its hierarchy, so no other category overrides it.

QuickIntell editorial content · Legacy registry date · Review not verified

Data effective
Data currency: ICD-10-CM to HCC mapping PY2027 initial (effective dates of service 2026, payment year 2027); CMS-HCC V28 model software V2826.115.T2 (effective payment year 2027). Next CMS release: PY2027 midyear final mapping (spring 2027) and PY2028 proposed model (February 2027).
Mapped ICD-10-CM codes
37
Factor, community non-dual aged
0.381
Factor, institutional
0.728
Hierarchy
Top of hierarchy

Relative factors by segment

Each segment is a separate regression; the factor is added to the beneficiary's demographic factors and other categories, then normalized and reduced by the coding intensity adjustment before it meets the plan's base rate. A factor of 1.000 equals the expected cost of an average beneficiary.

CMS-HCC V28 relative factors for HCC 6 by model segment
SegmentModel codeRelative factor
Community, non-dual, agedCNA_HCC60.381
Community, non-dual, disabledCND_HCC60.763
Community, full-benefit dual, agedCFA_HCC60.588
Community, full-benefit dual, disabledCFD_HCC60.833
Community, partial-benefit dual, agedCPA_HCC60.518
Community, partial-benefit dual, disabledCPD_HCC60.685
Long-term institutionalINS_HCC60.728

Hierarchy

HCC 6 is not part of a hierarchy: it is paid whenever a mapped diagnosis is documented, independently of the beneficiary's other categories.

ICD-10-CM codes that map to HCC 6

37 codes map to this category in the PY2027 initial mapping, concentrated in the B46 (8), B45 (7), B44 (6), B25 (5), B37 (3), A31 (2) code families. Descriptions are the CMS mapping descriptions for the FY2026 code set; a code that is deleted or split in the October code update stays valid for dates of service before the change.

ICD-10-CM codes mapped to HCC 6 in the CMS PY2027 initial mapping
ICD-10-CMDescription
A072Cryptosporidiosis
A310Pulmonary mycobacterial infection
A312Disseminated mycobacterium avium-intracellulare complex (DMAC)
B250Cytomegaloviral pneumonitis
B251Cytomegaloviral hepatitis
B252Cytomegaloviral pancreatitis
B258Other cytomegaloviral diseases
B259Cytomegaloviral disease, unspecified
B371Pulmonary candidiasis
B377Candidal sepsis
B3781Candidal esophagitis
B440Invasive pulmonary aspergillosis
B441Other pulmonary aspergillosis
B442Tonsillar aspergillosis
B447Disseminated aspergillosis
B4489Other forms of aspergillosis
B449Aspergillosis, unspecified
B450Pulmonary cryptococcosis
B451Cerebral cryptococcosis
B452Cutaneous cryptococcosis
B453Osseous cryptococcosis
B457Disseminated cryptococcosis
B458Other forms of cryptococcosis
B459Cryptococcosis, unspecified
B460Pulmonary mucormycosis
B461Rhinocerebral mucormycosis
B462Gastrointestinal mucormycosis
B463Cutaneous mucormycosis
B464Disseminated mucormycosis
B465Mucormycosis, unspecified
B468Other zygomycoses
B469Zygomycosis, unspecified
B484Penicillosis
B488Other specified mycoses
B582Toxoplasma meningoencephalitis
B583Pulmonary toxoplasmosis
B59Pneumocystosis

Where these codes sat in the V22 model

The V28 recalibration renumbered and regrouped categories; this table shows which legacy V22 categories the same ICD-10 codes belonged to, which is the quickest way to reconcile a V22-era HCC gap list with the current model.

V22 categories that the HCC 6 codes mapped to
V22 HCCCodes
637

Capturing and defending the category

A category counts for a payment year when a mapped diagnosis is documented at least once during the data collection year by an acceptable provider type at a face-to-face or audio-video encounter, and when the note shows the condition was monitored, evaluated, assessed or treated. Chronic conditions do not carry forward: a category that is not re-documented in the year drops out of the score, which is why annual wellness visits and problem-list reconciliation are where most recapture happens. Risk adjustment data validation audits sample enrollees and ask for the medical record behind each submitted category; an unsupported category is removed and, under the extrapolation rules, the error rate is applied across the contract. The QuickIntell risk adjustment product surfaces suspected and unsupported categories from the chart, and the HCC hub lists every V28 category with its factor and code count.

Frequently asked questions

Which ICD-10 codes map to HCC 6?

37 ICD-10-CM codes map to HCC 6 in the CMS PY2027 initial mapping, for example A072 Cryptosporidiosis; A310 Pulmonary mycobacterial infection; A312 Disseminated mycobacterium avium-intracellulare complex (DMAC); B250 Cytomegaloviral pneumonitis. The full list is on this page; a code counts only when it is documented at a face-to-face or video encounter in the data collection year and supported by the record.

How much does HCC 6 add to a risk score?

The V28 relative factor for HCC 6 is 0.381 for a community, non-dual, aged beneficiary, 0.588 for full-benefit dual aged, 0.763 for non-dual disabled and 0.728 for long-term institutional members. A factor of 1.000 equals the expected annual cost of an average beneficiary, so the category's share of the payment follows the plan's base rate for that segment.

Does HCC 6 count together with related categories?

HCC 6 is not part of a hierarchy, so it is paid whenever it is documented regardless of which other categories the beneficiary has.

What has to be documented for HCC 6 to be valid?

The diagnosis must be recorded by an acceptable provider type during a face-to-face or audio-video encounter in the service year, with the note showing that the condition was monitored, evaluated, assessed or treated. Risk adjustment data validation audits recover payment for categories the record does not support, so the code on the claim and the assessment in the note must match.

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-02. Verify against the primary file before billing or contracting decisions.

Disclaimer

Relative factors and mappings are reproduced from the CMS risk adjustment model files as an operational reference. Payment depends on the plan's base rate, normalization, the coding intensity adjustment and the enrollee's segment. Not legal, clinical or billing advice.