MS-DRG · FY 2026 v43.0
MS-DRG 645 – Endocrine Disorders without CC/MCC
A Medical DRG in MDC 10 (Endocrine, Nutritional & Metabolic Diseases & Disorders). Inpatient cases group to DRG 645 when the ICD-10-CM principal diagnosis is one of the 199 codes listed below and no secondary diagnosis on the CC or MCC lists is present. Its FY 2026 relative weight is 0.7683 with a geometric mean length of stay of 2.7 days.
Medical DRG – assigned by principal diagnosis✓ Official CMS v43.0 dataset
0.7683
Relative Weight
2.7
Geometric Mean LOS (days)
3.2
Arithmetic Mean LOS (days)
199
Principal Diagnosis Codes
Severity family
DRG 643with MCCWeight 1.6461 · GMLOS 4.9 daysDRG 644with CCWeight 1.0250 · GMLOS 3.4 daysDRG 645without CC/MCCWeight 0.7683 · GMLOS 2.7 days
How a case is assigned to DRG 645
The grouper first assigns the case to MDC 10 from the principal diagnosis and finds no qualifying operating-room procedure (this is a Medical DRG; ICD-10-PCS codes do not drive assignment here), then applies the severity split from secondary diagnoses: with MCC → 643; with CC → 644; without CC/MCC → 645.
ICD-10-CM
Principal Diagnosis Codes 199 codes · 38 categories
199 of 199 shown
A18 Tuberculosis of other organs2 codes
B67 Echinococcosis1 code
- B67.31 Echinococcus granulosus infection, thyroid gland
C73 Malignant neoplasm of thyroid gland1 code
- C73 Malignant neoplasm of thyroid gland
C74 Malignant neoplasm of adrenal gland9 codes
- C74.00 Malignant neoplasm of cortex of unspecified adrenal gland
- C74.01 Malignant neoplasm of cortex of right adrenal gland
- C74.02 Malignant neoplasm of cortex of left adrenal gland
- C74.10 Malignant neoplasm of medulla of unspecified adrenal gland
- C74.11 Malignant neoplasm of medulla of right adrenal gland
- C74.12 Malignant neoplasm of medulla of left adrenal gland
- C74.90 Malignant neoplasm of unspecified part of unspecified adrenal gland
- C74.91 Malignant neoplasm of unspecified part of right adrenal gland
- C74.92 Malignant neoplasm of unspecified part of left adrenal gland
C75 Malignant neoplasm of other endocrine glands and related structures5 codes
C79 Secondary malignant neoplasm of other and unspecified sites3 codes
D13 Benign neoplasm of other and ill-defined parts of digestive system1 code
- D13.7 Benign neoplasm of endocrine pancreas
D34 Benign neoplasm of thyroid gland1 code
- D34 Benign neoplasm of thyroid gland
D35 Benign neoplasm of other and unspecified endocrine glands8 codes
- D35.00 Benign neoplasm of unspecified adrenal gland
- D35.01 Benign neoplasm of right adrenal gland
- D35.02 Benign neoplasm of left adrenal gland
- D35.1 Benign neoplasm of parathyroid gland
- D35.2 Benign neoplasm of pituitary gland
- D35.3 Benign neoplasm of craniopharyngeal duct
- D35.7 Benign neoplasm of other specified endocrine glands
- D35.9 Benign neoplasm of endocrine gland, unspecified
D44 Neoplasm of uncertain behavior of endocrine glands8 codes
- D44.0 Neoplasm of uncertain behavior of thyroid gland
- D44.10 Neoplasm of uncertain behavior of unspecified adrenal gland
- D44.11 Neoplasm of uncertain behavior of right adrenal gland
- D44.12 Neoplasm of uncertain behavior of left adrenal gland
- D44.2 Neoplasm of uncertain behavior of parathyroid gland
- D44.3 Neoplasm of uncertain behavior of pituitary gland
- D44.4 Neoplasm of uncertain behavior of craniopharyngeal duct
- D44.9 Neoplasm of uncertain behavior of unspecified endocrine gland
D49 Neoplasms of unspecified behavior1 code
- D49.7 Neoplasm of unspecified behavior of endocrine glands and other parts of nervous system
E00 Congenital iodine-deficiency syndrome4 codes
E01 Iodine-deficiency related thyroid disorders and allied conditions4 codes
E02 Subclinical iodine-deficiency hypothyroidism1 code
- E02 Subclinical iodine-deficiency hypothyroidism
E03 Other hypothyroidism7 codes
- E03.0 Congenital hypothyroidism with diffuse goiter
- E03.1 Congenital hypothyroidism without goiter
- E03.2 Hypothyroidism due to medicaments and other exogenous substances
- E03.3 Postinfectious hypothyroidism
- E03.4 Atrophy of thyroid (acquired)
- E03.8 Other specified hypothyroidism
- E03.9 Hypothyroidism, unspecified
E04 Other nontoxic goiter5 codes
E05 Thyrotoxicosis [hyperthyroidism]14 codes
- E05.00 Thyrotoxicosis with diffuse goiter without thyrotoxic crisis or storm
- E05.01 Thyrotoxicosis with diffuse goiter with thyrotoxic crisis or storm
- E05.10 Thyrotoxicosis with toxic single thyroid nodule without thyrotoxic crisis or storm
- E05.11 Thyrotoxicosis with toxic single thyroid nodule with thyrotoxic crisis or storm
- E05.20 Thyrotoxicosis with toxic multinodular goiter without thyrotoxic crisis or storm
- E05.21 Thyrotoxicosis with toxic multinodular goiter with thyrotoxic crisis or storm
- E05.30 Thyrotoxicosis from ectopic thyroid tissue without thyrotoxic crisis or storm
- E05.31 Thyrotoxicosis from ectopic thyroid tissue with thyrotoxic crisis or storm
- E05.40 Thyrotoxicosis factitia without thyrotoxic crisis or storm
- E05.41 Thyrotoxicosis factitia with thyrotoxic crisis or storm
- E05.80 Other thyrotoxicosis without thyrotoxic crisis or storm
- E05.81 Other thyrotoxicosis with thyrotoxic crisis or storm
- E05.90 Thyrotoxicosis, unspecified without thyrotoxic crisis or storm
- E05.91 Thyrotoxicosis, unspecified with thyrotoxic crisis or storm
E06 Thyroiditis7 codes
E07 Other disorders of thyroid4 codes
E16 Other disorders of pancreatic internal secretion8 codes
- E16.0 Drug-induced hypoglycemia without coma
- E16.1 Other hypoglycemia
- E16.3 Increased secretion of glucagon
- E16.8 Other specified disorders of pancreatic internal secretion
- E16.9 Disorder of pancreatic internal secretion, unspecified
- E16.A1 Hypoglycemia level 1
- E16.A2 Hypoglycemia level 2
- E16.A3 Hypoglycemia level 3
E20 Hypoparathyroidism8 codes
- E20.0 Idiopathic hypoparathyroidism
- E20.810 Autosomal dominant hypocalcemia
- E20.811 Secondary hypoparathyroidism in diseases classified elsewhere
- E20.812 Autoimmune hypoparathyroidism
- E20.818 Other specified hypoparathyroidism due to impaired parathyroid hormone secretion
- E20.819 Hypoparathyroidism due to impaired parathyroid hormone secretion, unspecified
- E20.89 Other specified hypoparathyroidism
- E20.9 Hypoparathyroidism, unspecified
E21 Hyperparathyroidism and other disorders of parathyroid gland6 codes
E22 Hyperfunction of pituitary gland5 codes
E23 Hypofunction and other disorders of the pituitary gland6 codes
E24 Cushing's syndrome7 codes
E25 Adrenogenital disorders3 codes
E26 Hyperaldosteronism7 codes
E27 Other disorders of adrenal gland9 codes
- E27.0 Other adrenocortical overactivity
- E27.1 Primary adrenocortical insufficiency
- E27.2 Addisonian crisis
- E27.3 Drug-induced adrenocortical insufficiency
- E27.40 Unspecified adrenocortical insufficiency
- E27.49 Other adrenocortical insufficiency
- E27.5 Adrenomedullary hyperfunction
- E27.8 Other specified disorders of adrenal gland
- E27.9 Disorder of adrenal gland, unspecified
E29 Testicular dysfunction4 codes
E30 Disorders of puberty, not elsewhere classified4 codes
E31 Polyglandular dysfunction8 codes
- E31.0 Autoimmune polyglandular failure
- E31.1 Polyglandular hyperfunction
- E31.20 Multiple endocrine neoplasia [MEN] syndrome, unspecified
- E31.21 Multiple endocrine neoplasia [MEN] type I
- E31.22 Multiple endocrine neoplasia [MEN] type IIA
- E31.23 Multiple endocrine neoplasia [MEN] type IIB
- E31.8 Other polyglandular dysfunction
- E31.9 Polyglandular dysfunction, unspecified
E34 Other endocrine disorders18 codes
- E34.00 Carcinoid syndrome, unspecified
- E34.01 Carcinoid heart syndrome
- E34.09 Other carcinoid syndrome
- E34.1 Other hypersecretion of intestinal hormones
- E34.2 Ectopic hormone secretion, not elsewhere classified
- E34.30 Short stature due to endocrine disorder, unspecified
- E34.31 Constitutional short stature
- E34.321 Primary insulin-like growth factor-1 (IGF-1) deficiency
- E34.322 Insulin-like growth factor-1 (IGF-1) resistance
- E34.328 Other genetic causes of short stature
- E34.329 Unspecified genetic causes of short stature
- E34.39 Other short stature due to endocrine disorder
- E34.4 Constitutional tall stature
- E34.50 Androgen insensitivity syndrome, unspecified
- E34.51 Complete androgen insensitivity syndrome
- E34.52 Partial androgen insensitivity syndrome
- E34.8 Other specified endocrine disorders
- E34.9 Endocrine disorder, unspecified
E35 Disorders of endocrine glands in diseases classified elsewhere1 code
- E35 Disorders of endocrine glands in diseases classified elsewhere
E89 Postprocedural endocrine and metabolic complications and disorders, not elsewhere classified5 codes
Q89 Other congenital malformations, not elsewhere classified2 codes
R94 Abnormal results of function studies2 codes
S11 Open wound of neck6 codes
- S11.10XA Unspecified open wound of thyroid gland, initial encounter
- S11.11XA Laceration without foreign body of thyroid gland, initial encounter
- S11.12XA Laceration with foreign body of thyroid gland, initial encounter
- S11.13XA Puncture wound without foreign body of thyroid gland, initial encounter
- S11.14XA Puncture wound with foreign body of thyroid gland, initial encounter
- S11.15XA Open bite of thyroid gland, initial encounter
ICD-10-PCS
Procedure Codes
Procedure codes do not drive assignment for this DRG. DRG 645 is a Medical DRG, assigned from the principal diagnosis above.
Frequently Asked Questions
What is MS-DRG 645?
MS-DRG 645 (Endocrine Disorders without CC/MCC) is a medical DRG in MDC 10 (Endocrine, Nutritional & Metabolic Diseases & Disorders). Its FY 2026 relative weight is 0.7683 with a geometric mean length of stay of 2.7 days.
What is the difference between DRG 643, 644, 645?
All 3 share the same base category; the severity of secondary diagnoses separates them: 643 (with MCC), 644 (with CC), 645 (without CC/MCC). A major complication or comorbidity (MCC) places the case in the highest-weighted DRG of the family; a CC in the middle; neither in the lowest.
How many diagnosis codes group to DRG 645?
199 ICD-10-CM principal diagnosis codes group to this DRG, spanning 38 three-character categories.
What is the relative weight of DRG 645?
The FY 2026 relative weight of this DRG is 0.7683, meaning reimbursement of roughly 0.77 times the average Medicare inpatient case. Multiply by a hospital's blended base rate for the approximate payment.
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Source: CMS ICD-10 MS-DRG v43.0 Definitions Manual and the FY 2026 IPPS Final Rule (Table 5), effective October 1, 2025 through September 30, 2026. We publish the DRG assignments as CMS defines them and add the navigation, search, and code links.
