A59.9 ICD-10-CM Code: Trichomoniasis, unspecified
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Infections with a predominantly sexual mode of transmission (A50-A64)
A59.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceTrichomoniasis, unspecified
A parasitic infection caused by Trichomonas that affects the urinary and reproductive systems, but the specific location or type of infection is not documented. This is a sexually transmitted infection that can cause discharge, itching, and discomfort.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for A59.9 in this effective period.
Excludes 2
Official- intestinal trichomoniasis (A07.8)
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for A59.9 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for A59.9 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A59.9 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A59.9 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A59.9 in this effective period.
Buddy Documentation Tip
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is A59.9 an HCC code?
No. A59.9 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
A59.9 is the ICD-10-CM diagnosis code for trichomoniasis, unspecified. A parasitic infection caused by Trichomonas that affects the urinary and reproductive systems, but the specific location or type of infection is not documented. This is a sexually transmitted infection that can cause discharge, itching, and discomfort. A59.9 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering infections with a predominantly sexual mode of transmission (a50-a64).
A59.9 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Use A59.9 only when the documentation does not specify the site of trichomoniasis (such as urethritis, cervicitis, or prostatitis); if a specific site is documented, use the more specific A59.0-A59.8 codes instead.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A59.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use A59.9 only when the documentation does not specify the site of trichomoniasis (such as urethritis, cervicitis, or prostatitis); if a specific site is documented, use the more specific A59.0-A59.8 codes instead
- •Verify whether the patient is male or female and review clinical notes for any mention of specific symptoms or affected anatomical sites, as this may allow for a more specific code assignment