H10.421Simple chronic conjunctivitis, right eye

H10.421 is the ICD-10-CM diagnosis code for simple chronic conjunctivitis, right eye. It belongs to category H10 (conjunctivitis), block H10-H11 (disorders of conjunctiva) and chapter 7 (diseases of the eye and adnexa). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within H10.42 (simple chronic conjunctivitis), H10.421 is specifically for simple chronic conjunctivitis, right eye. Related codes cover left eye (H10.422), bilateral (H10.423) and unspecified eye (H10.429).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 124 (Other Disorders of the Eye with MCC or Thrombolytic Agent, relative weight 1.2471) and DRG 125 (Other Disorders of the Eye without MCC, relative weight 0.7702), in MDC 02 (Diseases and Disorders of the Eye), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 372.11 (simple chronic conjunctivitis).