What is ICD-10 code D75.84?

D75.84 is the ICD-10-CM diagnosis code for Other platelet-activating anti-PF4 disorders. It belongs to the ICD-10-CM chapter for diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (d50-d89). D75.84 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. D75.84 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. D75.84 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. D75.84 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does D75.84 map to under V28?

D75.84 maps to CMS-HCC V28 112 (Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions). The category number and label come from the CMS-HCC V28 model file for payment year 2026.

What does D75.84 pay in RAF?

D75.84 carries a community, non-dual, aged (CNA) RAF weight of 0.450 under CMS-HCC V28 for payment year 2026. The weight comes from the CMS V28 relative-factor file, not a hand-typed table.

What documentation supports D75.84?

This code is typically used for heparin-induced thrombocytopenia (HIT) or similar immune-mediated platelet disorders; ensure clinical documentation clearly supports the anti-PF4 antibody diagnosis Verify that this is not a case of drug-induced thrombocytopenia that would require an additional external cause code (Chapter 20) to identify the triggering medication Because D75.84 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score. See the MEAT criteria checklist at /meat-criteria for what Monitor, Evaluate, Assess, or Treat looks like in a note. MEAT is generic documentation evidence, not a payer-specific rule.

2026 ICD-10-CM D75.84: Other | HCC 112 RAF 0.450

D75.84 maps to CMS-HCC V28 112 (RAF 0.450). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools

ICD-10-CM Code View

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Code lookupD75.84Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89) / Other disorders of blood and blood-forming organs (D70-D77)

D75.84

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Other platelet-activating anti-PF4 disorders

This is a rare blood disorder where the immune system produces antibodies that attack platelets (blood cells that help with clotting) in response to a substance called PF4 (platelet factor 4). This condition can lead to abnormally low platelet counts and increased risk of blood clots.

Buddy Insight

Other platelet-activating anti-PF4 disorders encompass rare immune-mediated conditions where antibodies against platelet factor 4 activate platelets outside the context of heparin exposure.

CMS-HCC V28

Mapped

HCC 112

Immune Thrombocytopenia and S...

RAF 0.450

CMS-HCC V24

Mapped

HCC 48

Coagulation Defects and Other...

RAF 0.192

ACA/HHS

Mapped

HCC 75

HHS-HCC 75

Varies by metal level

ESRD/PACE

Mapped

HCC 48

Coagulation Defects and Other...

RAF 0.063

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

D75Other and unspecified diseases of blood and blood-forming organs

D75.8Other specified diseases of blood and blood-forming organs

D75.84Other platelet-activating anti-PF4 disorders

Inclusion Terms

Official

Spontaneous heparin-induced thrombocytopenia syndrome (without heparin exposure)
Thrombosis with thrombocytopenia syndrome
Vaccine-induced thrombotic thrombocytopenia

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for D75.84 in this effective period.

Related Child Codes

Official

D75.81Myelofibrosis

D75.82Heparin induced thrombocytopenia (HIT)

D75.83Thrombocytosis

D75.89Other specified diseases of blood and blood-forming organs

Includes

Official

ICD-10-CM does not list Includes notes for D75.84 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for D75.84 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for D75.84 in this effective period.

Use Additional

Official

code, if applicable, for adverse effect of other viral vaccine (T50.B95-)

Code Also

Official

ICD-10-CM does not list Code Also instructions for D75.84 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation must establish the presence of anti-PF4 antibodies confirmed by laboratory testing (enzyme immunoassay or functional assay) and specify that the condition is not caused by heparin exposure.

Include platelet counts, thrombotic events if present, the triggering factor (vaccine, spontaneous), and the treatment plan including alternative anticoagulation strategies.

Document any associated thrombosis location and severity.

MEAT Support

HCC Buddy guidance

Include platelet counts, thrombotic events if present, the triggering factor (vaccine, spontaneous), and the treatment plan including alternative anticoagulation strategies.

Document any associated thrombosis location and severity.

Audit Caution

HCC Buddy guidance

This code is specifically for anti-PF4 disorders NOT caused by heparin.

If heparin exposure triggered the condition, assign D75.821 instead.

The distinction is critical because treatment differs and incorrect coding may lead to inappropriate heparin re-exposure in future encounters.

Ensure documentation clearly states the non-heparin trigger.

Common Mistakes

HCC Buddy guidance

D75.821 (immune-mediated heparin-induced thrombocytopenia which requires heparin exposure as the trigger), D75.828 (other heparin-induced thrombocytopenia variants still linked to heparin), D68.69 (other thrombophilia not mediated by anti-PF4 antibodies), D69.59 (other secondary thrombocytopenia without the anti-PF4 mechanism).

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is D75.84 an HCC code?

Yes. D75.84 (Other platelet-activating anti-PF4 disorders) maps to Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions under the CMS-HCC V28 risk adjustment model (and Coagulation Defects and Other Specified Hematological Disorders under V24), with a community non-dual aged RAF of 0.450. It is billable for payment year 2026.

Coder answer: D75.84 is billable and maps to V28 HCC 112, Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: D75.84
Description: Other platelet-activating anti-PF4 disorders
HCC (V28): HCC 112 — Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions
RAF: 0.450
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 112, Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions

0.450

V24HCC 48, Coagulation Defects and Other Specified Hematological Disorders

0.192

ESRDHCC 48, Coagulation Defects and Other Specified Hematological Disorders

0.063

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work D75.84 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for D75.84

For D75.84 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed D75.84 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

D75.84 is the ICD-10-CM diagnosis code for other platelet-activating anti-pf4 disorders. This is a rare blood disorder where the immune system produces antibodies that attack platelets (blood cells that help with clotting) in response to a substance called PF4 (platelet factor 4). This condition can lead to abnormally low platelet counts and increased risk of blood clots. D75.84 sits in the ICD-10-CM chapter for diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (d50-d89), within the section covering other disorders of blood and blood-forming organs (d70-d77).

Under the CMS-HCC V28 risk adjustment model, D75.84 maps to Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions (HCC 112) with a community, non-dual, aged base RAF weight of 0.450. Under the older CMS-HCC V24 model, D75.84 maps to Coagulation Defects and Other Specified Hematological Disorders (HCC 48) with a community, non-dual, aged base RAF weight of 0.192. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

This code is typically used for heparin-induced thrombocytopenia (HIT) or similar immune-mediated platelet disorders; ensure clinical documentation clearly supports the anti-PF4 antibody diagnosis. Because D75.84 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for D75.84 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This code is typically used for heparin-induced thrombocytopenia (HIT) or similar immune-mediated platelet disorders; ensure clinical documentation clearly supports the anti-PF4 antibody diagnosis
•Verify that this is not a case of drug-induced thrombocytopenia that would require an additional external cause code (Chapter 20) to identify the triggering medication

Clinical Significance

Other platelet-activating anti-PF4 disorders encompass rare immune-mediated conditions where antibodies against platelet factor 4 activate platelets outside the context of heparin exposure. These disorders, including spontaneous heparin-induced thrombocytopenia and vaccine-induced immune thrombocytopenia and thrombosis, can cause severe thrombotic events and profound thrombocytopenia requiring urgent management.

Documentation Requirements

✓Documentation must establish the presence of anti-PF4 antibodies confirmed by laboratory testing (enzyme immunoassay or functional assay) and specify that the condition is not caused by heparin exposure.
✓Include platelet counts, thrombotic events if present, the triggering factor (vaccine, spontaneous), and the treatment plan including alternative anticoagulation strategies.
✓Document any associated thrombosis location and severity.

Use Additional Code

code, if applicable, for adverse effect of other viral vaccine (T50.B95-)

Commonly Confused Codes

•D75.821 (immune-mediated heparin-induced thrombocytopenia which requires heparin exposure as the trigger), D75.828 (other heparin-induced thrombocytopenia variants still linked to heparin), D68.69 (other thrombophilia not mediated by anti-PF4 antibodies), D69.59 (other secondary thrombocytopenia without the anti-PF4 mechanism).