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E03.9 — Hypothyroidism, unspecified
E03.9
What this code means
Hypothyroidism is an underactive thyroid gland, slowing metabolism and causing tiredness, weight gain and cold sensitivity.
Also called: hypothyroidism, underactive thyroid.
When this code is used
Used for hypothyroidism when the cause is not specified.
Where it sits in ICD-10-CM
Code E03.9 belongs to Chapter 4: Endocrine, nutritional and metabolic diseases, which covers codes E00–E89 in the FY2027 ICD-10-CM tabular list. The official description above is copied verbatim from the CDC/NCHS FY2027 code file.
Related symptoms
Related anatomy
Watch: related videos
Frequently asked questions
What is ICD-10-CM code E03.9?
E03.9 is the ICD-10-CM diagnosis code for “Hypothyroidism, unspecified”. Hypothyroidism is an underactive thyroid gland, slowing metabolism and causing tiredness, weight gain and cold sensitivity.
When is code E03.9 used?
Used for hypothyroidism when the cause is not specified. It belongs to Chapter 4 of ICD-10-CM (Endocrine, nutritional and metabolic diseases).
This guide explains ICD-10-CM codes in plain language for patients, students and other readers. It is educational information only — not coding, billing or medical advice. The code recorded for any real encounter is assigned from the full clinical documentation by the treating team and qualified coders, and only they can decide which code fits a specific case.