E29.1: Testicular hypofunction

The ICD-10-CM code for low testosterone arising from primary testicular failure is E29.1, which the Alphabetic Index reaches directly from the entry hypogonadism, male.

Billable

FY2027

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At a glance

Code Family

E29: Testicular dysfunction

Condition

Low testosterone

DRG Grouping

MS-DRG 643, 644 or 645, endocrine disorders, in MDC 10 under the FY2027 MS-DRG v44 grouper, depending on complications and comorbidities.

HCC Mapping (v28)

E29.1 was not identified in any CMS-HCC v28 category. The v28 endocrine and metabolic categories are HCC 35 through HCC 38 and HCC 48 through HCC 51.

Family Specificity

Four billable codes that split only on the direction of testicular dysfunction. The fork that decides the code sits outside the family, between primary testicular failure at E29.1 and central hypogonadotropic causes at E23.0.

Effective Date

Valid in the FY2026 code set. The FY2027 update revises one inclusion term and leaves the descriptor and notes unchanged.

Which E29 code do I assign?

Category E29 splits only on the direction of testicular dysfunction: hyperfunction, hypofunction, other or unspecified. The fork that actually decides the code runs across categories, separating primary testicular failure at E29.1 from central hypogonadotropic causes at E23.0 on the basis of serum LH and FSH.

When documentation says…

Code

Low morning total testosterone with elevated LH and FSH

E29.1

Primary testicular failure. This is the landing code for male hypogonadism recorded without further qualification. The note must carry the low testosterone value and the raised gonadotropins, or state primary or testicular hypogonadism in words.

Low testosterone with low or inappropriately normal LH and FSH

E23.0

Secondary hypogonadism originating in the pituitary or the hypothalamus. E23.0 carries hypogonadotropic hypogonadism, Kallmann's syndrome, fertile eunuch syndrome and isolated deficiency of gonadotropin as inclusion terms. Isolated gonadotropin deficiency is an Excludes1 at E29. E29.1 is not reported for this pattern.

Testosterone deficiency following bilateral orchiectomy, pelvic radiation or other treatment

E89.5

Postprocedural testicular hypofunction. E89.5 is an Excludes1 sitting directly under E29.1. The record must tie the deficiency to the prior procedure or to the radiation.

47,XXY karyotype with low testosterone

Q98.0

Klinefelter syndrome karyotype 47, XXY. Klinefelter's syndrome is an Excludes1 at E29 across Q98.0–Q98.1 and Q98.4. The karyotype result belongs in the record. Q98.4 covers Klinefelter syndrome documented without a stated karyotype.

Hypersecretion of testicular hormones

E29.0

Testicular hyperfunction, the opposite pole of the same category. Hypersecretion of testicular hormones is the inclusion term printed at E29.0.

A named testicular dysfunction that the tabular does not classify elsewhere

E29.8

Other testicular dysfunction. Use this only when the provider names a testicular dysfunction and no more specific code exists.

Testicular dysfunction with no direction stated

E29.9

Testicular dysfunction, unspecified. This is not the code for unqualified male hypogonadism, which the Alphabetic Index sends to E29.1.

Tabular notes

EXCLUDES1

E29.1 carries one Excludes1 note of its own, for postprocedural testicular hypofunction (E89.5). Category E29 adds Excludes1 notes for androgen insensitivity syndrome (E34.5-), azoospermia or oligospermia NOS (N46.0–N46.1), isolated gonadotropin deficiency (E23.0), and Klinefelter's syndrome (Q98.0–Q98.1, Q98.4). The block heading E20-E35 adds Excludes1 notes for galactorrhea (N64.3) and gynecomastia (N62). An Excludes1 note means the two codes are never reported together for the same condition. A record documenting Klinefelter syndrome or postprocedural testicular failure therefore does not also take E29.1.

USE ADDITIONAL

Use additional code for adverse effect, if applicable, to identify the drug, from T36–T50 with fifth or sixth character 5. Codes reached this way include T38.0X5 for glucocorticoids and synthetic analogues, T40.2X5 for other opioids, and T45.1X5 for antineoplastic and immunosuppressive drugs. Each of these requires a seventh character: A for the initial encounter, D for a subsequent encounter and S for sequela.

FY2027: EFFECTIVE 1 OCTOBER 2026

The FY2027 tabular addenda revise one inclusion term at E29.1. The FY2026 term 5-delta-Reductase deficiency (with male pseudohermaphroditism) now reads 5-Alpha-reductase deficiency (with male pseudohermaphroditism). The Alphabetic Index entry Deficiency, 5-alpha reductase leads to E29.1. The descriptor, the Excludes1 note for E89.5 and the Use Additional instruction are unchanged in the FY2027 update. E29.1 carries three inclusion terms: defective biosynthesis of testicular androgen NOS, 5-alpha-reductase deficiency with male pseudohermaphroditism, and testicular hypogonadism NOS.

Operational & financial impact

Why specificity matters beyond the chart: risk adjustment, DRG assignment and denial exposure all follow from which code is selected.

CMS-HCC v28 (PY2024+)

E29.1 was not identified in any CMS-HCC v28 category.

The v28 endocrine and metabolic categories are HCC 35 for pancreas transplant status, HCC 36, HCC 37 and HCC 38 for diabetes, HCC 48 for morbid obesity, HCC 49 for specified lysosomal storage disorders, HCC 50 for amyloidosis, porphyria and other specified metabolic disorders, and HCC 51 for Addison's and Cushing's diseases, acromegaly and other specified endocrine disorders.

E23.0 does not map to an HCC in the v28 crosswalk either. It mapped to HCC 23 under CMS-HCC v24.

MS-DRG v44 (FY2027)

MS-DRG 643: endocrine disorders with MCC.

MS-DRG 644: endocrine disorders with CC.

MS-DRG 645: endocrine disorders without CC/MCC.

An inpatient admission with E29.1 as principal diagnosis groups within MDC 10 to MS-DRG 643, 644 or 645 under the FY2027 MS-DRG v44 grouper. Which of the three applies depends on the presence and severity of complications or comorbidities.

Medicare and commercial payers

There is no National Coverage Determination addressing the diagnosis coding of male hypogonadism.

The Endocrine Society 2018 clinical practice guideline on testosterone therapy recommends confirming the diagnosis with repeated measurement of fasting morning total testosterone. Its recommendation 1.3 also directs clinicians to measure serum LH and FSH to distinguish primary testicular hypogonadism from secondary pituitary or hypothalamic hypogonadism.

Z79.890, hormone replacement therapy, describes the therapy rather than the diagnosis. It is reported in addition to the hypogonadism code, never in place of it.

An encounter whose only purpose is to check a testosterone level, with no diagnosis established, is not E29.1.

WHERE SPECIFICITY IS LOST

Assigning E29.1 when LH and FSH are low or inappropriately normal, which is the E23.0 pattern.

Assigning E29.1 after bilateral orchiectomy, pelvic radiation or another procedure, when E89.5 is an Excludes1 directly under E29.1.

Reporting E29.1 alongside Q98.0, Q98.1 or Q98.4 for the same hypogonadism, which the Excludes1 note at E29 forbids.

Reaching for E29.9 when the note says only male hypogonadism, which the Alphabetic Index sends to E29.1.

Omitting Z79.890 when the patient is on long-term testosterone replacement.

Omitting the adverse-effect code from T36–T50 when a drug is documented as the cause.

SEVERITY DESIGNATION (MS-DRG V44.0)

E29.1 carries no severity designation. It appears in neither Appendix G, the CC list, nor Appendix H, the MCC list, of the ICD-10 MS-DRG Definitions Manual Version 44.0. A case reaches a higher tier of its three-tier DRG family on a designation carried by another diagnosis.

Documentation checklist to support E29.1

Chart elements that support code selection and reduce specificity-driven denials.

The provider's statement of male hypogonadism, testicular hypofunction, testicular failure or androgen deficiency.

Serum total testosterone from a fasting morning sample, with the value and the collection date.

Serum LH and FSH, which separate primary testicular failure at E29.1 from secondary hypogonadotropic hypogonadism at E23.0.

Confirmation that no prior orchiectomy, pelvic radiation or other procedure is the documented cause, because postprocedural testicular hypofunction is E89.5 and an Excludes1 at E29.1.

A karyotype result where Klinefelter syndrome is suspected, because Q98.0, Q98.1 and Q98.4 are Excludes1 at E29.

Any drug named as the cause, to support the Use Additional adverse-effect code from T36–T50 with fifth or sixth character 5.

Current testosterone replacement therapy and its route, to support Z79.890.

For outpatient encounters, a confirmed diagnosis rather than a screening, rule-out or suspected statement.

FAQ

Is E29.1 a billable code?

Yes. E29.1 is a four-character code with no further subdivision in the FY2027 code set. It is valid for submission on its own. It is also a male-only diagnosis code, which triggers a sex-conflict edit if it is reported for a female patient.

What is the ICD-10 code for low testosterone?

E29.1, testicular hypofunction, is the code the Alphabetic Index reaches from hypogonadism, male and from deficiency, hormone, testicular. The tabular inclusion term at E29.1 is testicular hypogonadism NOS. ICD-10-CM has no main index term for testosterone. A note reading only low testosterone therefore routes through male hypogonadism to E29.1.

When do I use E23.0 instead of E29.1?

Use E23.0 when the failure is central rather than testicular. E23.0, hypopituitarism, carries hypogonadotropic hypogonadism, Kallmann's syndrome, fertile eunuch syndrome and isolated deficiency of gonadotropin as inclusion terms. Serum LH and FSH decide it. High gonadotropins point to primary testicular failure at E29.1. Low or inappropriately normal gonadotropins point to E23.0. Isolated gonadotropin deficiency is an Excludes1 at E29, which means the two are not reported together for the same hypogonadism.

Does E29.1 map to an HCC under CMS-HCC v28?

E29.1 was not identified in any CMS-HCC v28 category. The v28 endocrine and metabolic categories are HCC 35 through HCC 38 for pancreas transplant status and diabetes and HCC 48 through HCC 51 for obesity and specified endocrine and metabolic disorders. Risk adjustment status and inpatient severity designation are separate questions. Neither one follows from the other.

Can I code E29.1 with Klinefelter syndrome?

E29.1 is not coded with Klinefelter syndrome for the same hypogonadism. Klinefelter's syndrome is an Excludes1 at category E29, covering Q98.0–Q98.1 and Q98.4. A patient with a 47,XXY karyotype and low testosterone takes the Q98 code alone for the hypogonadism. Q98.4 applies when Klinefelter syndrome is documented without a stated karyotype.

What code covers low testosterone after orchiectomy or cancer treatment?

The code is E89.5, postprocedural testicular hypofunction. E89.5 is an Excludes1 sitting directly under E29.1, which rules E29.1 out once the record ties the deficiency to a prior procedure or to radiation. E89.3, postprocedural hypopituitarism, applies instead when the pituitary was the treated or irradiated structure. Where the cause is ongoing androgen deprivation with a GnRH agonist rather than surgery, Z79.818 identifies the long-term drug therapy.

Do I code long-term testosterone replacement separately?

Yes. Long-term testosterone replacement is coded with Z79.890, hormone replacement therapy. Z79.81 carries an Excludes1 pointing to Z79.890 for hormone replacement therapy, which confirms Z79.890 as the specific code. Z79.899, other long term (current) drug therapy, is the residual code and is used only where no more specific Z79 code fits. Category Z79 also instructs coders to code also any therapeutic drug level monitoring (Z51.81).

How is E29.1 sequenced in each setting?

Sequencing follows the reason for the encounter. E29.1 is the principal diagnosis on an inpatient claim only when the admission is for evaluation or management of the hypogonadism itself, which then groups to MS-DRG 643, 644 or 645. Otherwise it is reported as a secondary diagnosis. On the outpatient side only a confirmed diagnosis is coded. A suspected or rule-out statement is not coded in that setting. On the inpatient side an uncertain diagnosis documented at discharge may be coded as confirmed under UHDDS guidelines.

Related codes

Codes in the same family as E29.1. Only codes with a published page render as links.

Sibling codes in the E29 family

E29.0: Testicular hyperfunction.
E29.8: Other testicular dysfunction.
E29.9: Testicular dysfunction, unspecified.

Additional codes to consider

Codes outside the E29 family considered alongside E29.1.

Companion: code alongside when documented

Z79.890: Hormone replacement therapy, for long-term testosterone replacement (Guideline I.C.21.c.3).
Z79.899: Other long term (current) drug therapy, the residual code where no specific Z79 code fits (Guideline I.C.21.c.3).
Z79.818: Long term (current) use of other agents affecting estrogen receptors and estrogen levels, which carries GnRH agonists including leuprolide and goserelin as inclusion terms (Guideline I.C.21.c.3).
Z51.81: Encounter for therapeutic drug level monitoring, under the Code also note at category Z79.
T38.0X5-: Adverse effect of glucocorticoids and synthetic analogues, which requires a seventh character, under the Use additional note at E29.1.
T40.2X5-: Adverse effect of other opioids, which requires a seventh character, under the Use additional note at E29.1.
T45.1X5-: Adverse effect of antineoplastic and immunosuppressive drugs, which requires a seventh character, under the Use additional note at E29.1.

Consider instead

E23.0: Hypopituitarism, which carries hypogonadotropic hypogonadism and Kallmann's syndrome as inclusion terms.
E89.5: Postprocedural testicular hypofunction, where a procedure or radiation is the documented cause.
E89.3: Postprocedural hypopituitarism, where the pituitary was the treated structure.
Q98.0: Klinefelter syndrome karyotype 47, XXY.
Q98.1: Klinefelter syndrome, male with more than two X chromosomes.
Q98.4: Klinefelter syndrome, unspecified.
E34.50: Androgen insensitivity syndrome, unspecified, where the defect is receptor-level rather than testicular.
N46.0-: Azoospermia, a subcategory that requires further characters, where infertility rather than androgen deficiency is the documented problem.
N46.1-: Oligospermia, a subcategory that requires further characters.
N62: Hypertrophy of breast, which carries gynecomastia and is an Excludes1 at the E20-E35 block.
E30.0: Delayed puberty, for a constitutional delay in an adolescent.

Sources

All claims on this page derive from government and professional-standards sources.

National Center for Health Statistics. (2026). International classification of diseases, tenth revision, clinical modification (ICD-10-CM) FY2027 files. https://www.cdc.gov/nchs/icd/icd-10-cm/files.html
Centers for Medicare & Medicaid Services and National Center for Health Statistics. (2026). ICD-10-CM official guidelines for coding and reporting FY2027. https://ftp.cdc.gov/pub/Health_Statistics/NCHS/Publications/ICD10CM/2027/ICD-10-CM-October-1-2026-FY27-Guidelines.pdf
Centers for Medicare & Medicaid Services. (2025). 2026 model software/ICD-10 mappings. https://www.cms.gov/medicare/payment/medicare-advantage-rates-statistics/risk-adjustment/2026-model-software-icd-10-mappings
Centers for Medicare & Medicaid Services. (2026). MS-DRG classifications and software, version 44. https://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps/ms-drg-classifications-and-software