Sjögren syndrome with renal tubulo-interstitial involvement, capturing the specific manifestation of tubulointerstitial nephropathy — including renal tubular acidosis — as a direct complication of the systemic autoimmune disease.

Documentation tips

What should appear in the chart to support M35.04.

Source · Editorial brief grounded in 6 cited references ↓

• Provider must explicitly document both the Sjögren syndrome diagnosis and tubulo-interstitial nephropathy as a related manifestation — 'renal involvement' alone is not sufficient to support M35.04.
• Include laboratory findings supporting TIN or renal tubular acidosis: serum bicarbonate, urine pH, potassium, creatinine, and urinalysis with urine protein/creatinine ratio.
• Document whether Sjögren syndrome is primary or secondary; primary versus secondary distinction affects clinical context, though M35.04 does not differentiate — note this in the record for completeness.
• Note any positive serologic markers (anti-SSA/Ro, anti-SSB/La) and kidney biopsy findings if performed, as these substantiate the link between Sjögren syndrome and the renal diagnosis.
• If additional organ-system manifestations are documented (e.g., keratoconjunctivitis, interstitial lung disease), assess whether each meets criteria for its own sibling code under M35.0 and whether reporting multiple codes is warranted.

Related CPT procedures

Procedure codes commonly billed with M35.04. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

Common coding pitfalls

The recurring mistakes coders make with M35.04 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

• Defaulting to M35.00 (Sjögren syndrome, unspecified) when the record documents TIN — M35.04 is the correct billable code whenever tubulo-interstitial nephropathy is explicitly diagnosed.
• Confusing M35.04 with general chronic kidney disease codes (N18.x): TIN in Sjögren syndrome is coded at M35.04 as the primary connective-tissue disorder code; add a secondary renal code only when the provider documents a specific CKD stage or additional renal diagnosis.
• Reporting M35.04 based solely on abnormal renal labs without provider documentation linking the renal findings to Sjögren syndrome — query the provider before assigning.
• Using the non-billable parent code M35.0 instead of drilling to the appropriate fifth-character code; M35.0 is not a valid billing code — always select a specific child code such as M35.04.

Clinical context

Source · Editorial summary grounded in 6 cited references ↓

Inclusion & exclusion notes

Per the official ICD-10-CM Tabular List.

Source · CDC ICD-10-CM Official Tabular List · 2026

Sibling codes

Other billable codes under M35.0 (laterality / anatomic variants).