Final answer:
The ICD-10-CM code for essential hypertension is I10.
Step-by-step explanation:
The ICD-10-CM code for essential hypertension is I10. Hypertension is classified as essential when there is no identifiable cause for the elevated blood pressure. The code I10 is used to indicate primary or essential hypertension, while other codes are used for secondary hypertension, which is elevated blood pressure caused by an underlying condition or medication.