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Q55.0

Q55.0Absence and aplasia of testis

Billable / specific codeICD-10-CMPOA exempt

Q55.0 is a billable, specific ICD-10-CM code for absence and aplasia of testis. It is valid for submission on a claim.

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Monorchism

Risk adjustment

Q55.0 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Medicare coverage

Q55.0 is named in 2 Medicare coverage policies 2 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A56421Billing and Coding: CT of the Abdomen and Pelvis
  • A58828Billing and Coding: Treatment of Males with Low Testosterone

How Q55.0 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to Q55.0.

  • Anorchia, anorchism, anorchidism
  • Monorchism, monorchidism
  • Absencetestis(congenital)
  • Agenesistesticle
  • Aplasiatesticle
  • Malformationtestis and scrotumaplasia

Related codes at this level

Codes that share Q55. If Q55.0 is not quite right, the correct code is usually one of these.

Questions about Q55.0

Is Q55.0 a billable ICD-10-CM code?
Yes. Q55.0 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does Q55.0 sit in the tabular list?
Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0), in the block Congenital malformations of genital organs (Q50-Q56).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.