I woke up unable to hear in one ear. Is this an emergency, and what tests are needed?

Pure-tone audiometry: Measures the quietest sounds heard at different pitches and helps confirm the degree and pattern of sensorineural hearing loss.NNIDCDMMedlinePlus

Tuning-fork or bone-conduction testing: Helps distinguish inner-ear hearing loss from sound blocked by wax or middle-ear fluid.NNIDCDMMedlinePlus

Tympanometry: Checks eardrum and middle-ear movement when fluid, pressure, or another conductive problem is suspected.NNIDCDMMedlinePlus

MRI: May be ordered after one-sided sensorineural hearing loss to examine the auditory nerve and rule out structural causes.NNIDCDMMedlinePlus

Blood or balance tests: May be selected when symptoms or history suggest infection, autoimmune disease, another underlying condition, dizziness, or vertigo.NNIDCDMMedlinePlus

Sudden Deafness — NIDCD, National Institutes of Health: Primary source for urgency, diagnosis, additional tests, and treatment timing.

Hearing Tests for Adults — MedlinePlus, National Library of Medicine: Explains audiometry, bone-conduction testing, tympanometry, and hearing-loss types.

Why Does Sudden Hearing Loss Happen? — Cleveland Clinic: Practical care pathway and reasons not to dismiss a blocked-ear sensation.

Hearing loss — Healthdirect Australia: Government-supported overview of hearing-loss symptoms, assessment, and care.

Unilateral Hearing Loss — Cleveland Clinic: Background on one-sided hearing loss and longer-term management.