ICD-10-CM · Spine

M46.47

Inflammation of an intervertebral disc at the lumbosacral junction (L5-S1 level) where the causative organism or inflammatory mechanism has not been specified in the medical record.

Verified May 8, 2026 · 6 sources ↓

Status: Billable
Chapter: 13
Related CPT: 10
Region: Spine

Drawn from CDCICD10DataAAPCIcdlistCMS

Documentation tips

What should appear in the chart to support M46.47.

Source · Editorial brief grounded in 6 cited references ↓

Document the specific region by name — 'lumbosacral' — to justify M46.47 over M46.46 (lumbar) or M46.40 (site unspecified).
Record MRI findings explicitly: T2 hyperintensity within the disc, endplate erosion, and any paraspinal or epidural extension.
Include inflammatory lab markers (ESR, CRP) with values and date drawn; these support medical necessity and reduce audit risk on the unspecified code.
If cultures or biopsy results are pending at coding time, M46.47 is appropriate — update to M46.5x with organism code once the causative agent is confirmed.
Note the clinical basis for the inflammatory vs. degenerative distinction; imaging should reflect an inflammatory process before assigning any M46.4x code rather than a degenerative disc code.

Related CPT procedures

Procedure codes commonly billed with M46.47. Linking the right diagnosis to the right procedure is what establishes medical necessity.

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

72148 $191.72

Non-contrast MRI of the lumbar spine used to evaluate disc pathology, spinal stenosis, nerve root compression, and other structural abnormalities without administration of contrast material.

72158 $318.31

MRI of the lumbar spinal canal and its contents performed first without contrast, then repeated after contrast administration for enhanced visualization.

72100 $40.42

Radiologic examination of the lumbosacral spine capturing two or three views, used to evaluate the lumbar vertebrae and sacrum for injury, degeneration, or structural abnormality.

72110 $53.44

Radiologic examination of the lumbar spine (lumbosacral) with a minimum of four views, including oblique and/or bending views.

22612 $1,467.64

Posterior or posterolateral lumbar arthrodesis of a single interspace, performed via a posterior approach with bone graft and typically pedicle screw fixation to achieve vertebral segment fusion.

22630 $1,510.72

Posterior interbody arthrodesis of a single lumbar interspace, including laminectomy and/or discectomy performed to prepare the interspace for fusion rather than for decompression.

22558 $1,423.88

Anterior interbody arthrodesis of the lumbar spine using an anterior or anterolateral approach, including the minimal discectomy required to prepare the interspace for fusion.

63030 $898.15

Single-interspace lumbar laminotomy with nerve root decompression, including partial facetectomy, foraminotomy, and/or herniated disc excision performed via open surgical technique.

62323 View procedure details

72131 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M46.47 and adjacent codes.

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

Assigning M46.46 (lumbar region) when the provider documents lumbosacral — the lumbosacral disc (L5-S1) has its own distinct code M46.47 and should not be collapsed into the lumbar region code.
Using M46.47 when an organism has been identified; a confirmed infectious agent requires M46.5x (Other infective spondylopathies, lumbosacral region = M46.57) plus a secondary organism code.
Selecting M46.47 based on degenerative disc changes on imaging alone — imaging must reflect an inflammatory process (endplate erosion, disc space T2 signal) rather than simple spondylosis.
Failing to sequence the underlying systemic condition first when discitis is a manifestation of a coded etiology subject to etiology/manifestation convention.
Missing MCC documentation that would shift MS-DRG from 552 to the higher-weighted 551 — audit the comorbidity list before final coding.

Clinical context

Source · Editorial summary grounded in 6 cited references ↓

M46.47 applies when the provider documents discitis — or synonymous terms such as lumbosacral discitis or discitis of the lumbosacral spine — localized to the lumbosacral region, and the etiology (infectious organism, pyogenic vs. non-pyogenic) remains unspecified. Imaging typically shows T2 hyperintensity on MRI with endplate erosion; elevated ESR and CRP are common laboratory correlates. The 'unspecified' designation reflects the absence of documented organism or mechanism, not the absence of pathology.

If the organism is identified (e.g., Staphylococcus aureus), step up to M46.5x (Other infective spondylopathies) with the lumbosacral 7th site character and add a secondary code for the causative organism. If the inflammation is purely a manifestation of an identified systemic inflammatory condition, consider whether the spondylopathy codes under M45–M46 are still appropriate or whether the underlying condition must be sequenced first per etiology/manifestation coding conventions.

M46.47 groups into MS-DRG v43.0 551 (Medical back problems with MCC) or 552 (Medical back problems without MCC), so thorough documentation of comorbidities that qualify as MCCs directly affects DRG weight and reimbursement. Do not downcode to M46.46 (lumbar region) when the provider explicitly documents lumbosacral involvement — the lumbosacral region spans the L5-S1 disc and is distinct from the purely lumbar (L1-L4/5) segment.

Sibling codes

Other billable codes under M46.4 (laterality / anatomic variants).

M46.42

Discitis, unspecified, cervical region

M46.40

Discitis, unspecified, site unspecified

M46.41

Discitis, unspecified, occipito-atlanto-axial region

M46.49

Discitis, unspecified, multiple sites in spine

M46.48

Discitis, unspecified, sacral and sacrococcygeal region

M46.44

Discitis, unspecified, thoracic region

M46.43

Discitis, unspecified, cervicothoracic region

M46.46

Discitis, unspecified, lumbar region

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01What is the difference between M46.47 and M46.46?

M46.46 is discitis of the lumbar region (roughly L1–L4/5); M46.47 is discitis of the lumbosacral region, specifically involving the L5-S1 disc level. Use whichever matches the provider's documented anatomic location — do not default to lumbar when lumbosacral is documented.

02Can I use M46.47 when the causative organism is still unknown pending culture?

Yes. M46.47 is appropriate when etiology is genuinely unspecified or pending. If cultures later confirm an organism, update the claim or flag the encounter for addendum coding to M46.57 plus the appropriate organism code.

03Does M46.47 require imaging confirmation before coding?

The ICD-10-CM code itself does not mandate imaging, but payers and auditors expect documentation that supports an inflammatory disc process. MRI showing T2 hyperintensity and endplate erosion, combined with elevated ESR or CRP, constitutes the strongest clinical support.

04When should I use M46.57 instead of M46.47?

Use M46.57 (Other infective spondylopathies, lumbosacral region) when a specific infectious organism has been identified. Add a secondary code for the causative pathogen. M46.47 is reserved for cases where the organism or mechanism remains unspecified.

05Which MS-DRGs does M46.47 map to?

M46.47 groups to MS-DRG v43.0 551 (Medical back problems with MCC) or 552 (Medical back problems without MCC). Documenting qualifying MCCs — such as sepsis or respiratory failure — shifts the encounter to the higher-weighted DRG 551.

06Is M46.47 appropriate for a postoperative disc space infection after lumbar fusion?

Post-procedural infections generally require a postprocedural complication code (e.g., T81.4x series for infection following a procedure) sequenced first. M46.47 may be used as an additional code to describe the site-specific condition, but the complication code should lead unless the provider's documentation clearly supports otherwise.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

Mira AI Scribe captures the provider's explicit lumbosacral region designation, MRI findings (T2 disc hyperintensity, endplate erosion), inflammatory lab values (ESR, CRP with results), and any culture or biopsy status — preventing a downcode to M46.40 (unspecified site) or M46.46 (lumbar), and flagging when a confirmed organism should trigger reassignment to M46.57.

See how Mira captures M46.47 documentation