Glossary · Clinical

Autograft

An autograft is tissue—most commonly bone, tendon, or cartilage—harvested from the same patient who will receive it, eliminating rejection risk and providing the biologic stimulus for successful incorporation.

Verified May 8, 2026 · 7 sources ↓

Drawn from CMSAAOSAAPCICD10DataNovitas

Definition

Source · Editorial summary grounded in 7 cited references ↓

An autograft uses the patient's own tissue as the transplanted material. In orthopedics, bone autograft is the gold standard for promoting fusion and healing because it supplies three essential properties simultaneously: an osteoconductive scaffold, osteoinductive growth signals, and living osteogenic cells. Common donor sites include the iliac crest, proximal tibia, distal radius, and—during spine procedures—local bone fragments from the same surgical field (spinous process, lamina, or rib).

The harvested material is classified by its physical form and intended function. Morselized (cancellous) autograft fills voids and accelerates biologic incorporation. Structural autograft retains cortical integrity and provides immediate mechanical support. In spine surgery, CPT distinguishes three autograft add-on codes based on harvest location and technique: local graft from the same incision, morselized graft from a separate incision or site, and structural cortical or corticocancellous graft from a separate site.

Autograft carries real trade-offs. Harvest adds operative time, creates a second wound, and introduces donor-site morbidity—pain, hematoma, and rarely nerve injury—that can outlast the index procedure. These downsides have driven interest in allografts and synthetic bone substitutes, but autograft remains the benchmark against which alternatives are measured for biologic efficacy.

Why it matters

Coding autograft incorrectly is one of the most audited patterns in spine and musculoskeletal surgery billing. The three spine-specific autograft add-on codes (20936, 20937, 20938) are mutually exclusive with each other and each carries a Medicare MUE of one unit per operative encounter regardless of how many vertebral levels are fused—reporting multiple units or stacking incompatible codes triggers NCCI PTP edits and automatic claim denial. Confusing autograft with allograft (20931) creates a misrepresentation of the procedure that can rise to the level of a false claim. Getting the distinction right also affects clinical documentation: if the operative note does not specify harvest site, graft form (morselized vs. structural), and incision used, the supporting code cannot be defended on audit.

Common mistakes

Where people most often go wrong with this concept.

Source · Editorial brief grounded in cited references ↓

Reporting both 20936 (local autograft, same incision) and 20937 or 20938 (separate-incision autograft) on the same spine claim—these codes are mutually exclusive; only one autograft add-on is allowed per operative session under NCCI policy.
Billing more than one unit of 20937 or 20938 because multiple vertebral levels were fused—CMS sets the MUE at 1 unit per procedure date regardless of level count.
Using an autograft CPT code when the surgeon actually implanted donor-bank (allograft) material—confusing the two graft sources can constitute a coding misrepresentation.
Omitting the autograft add-on code entirely when local bone fragments from the same incision are packed into a fusion bed, leaving reimbursement on the table for a separately reportable service.
Failing to document donor-site specifics (harvest location, graft morphology, separate vs. same incision) in the operative note, making the chosen code indefensible during payer audit or RAC review.
Applying skin-graft autograft codes (e.g., 15110 series) to bone-graft procedures—these are distinct code families with different clinical contexts and payer edits.

Related codes

Codes commonly involved when this concept appears in practice.

CPT

ICD-10

M96.89

Modifiers

59 Distinct procedural service 79 Unrelated procedure during postop AS PA / NP / CNS assistant at surgery

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 7 cited references ↓

01Can I bill for autograft harvesting separately when it is performed at the same incision as the primary spine procedure?

No. Add-on code 20936 covers local autograft obtained through the same incision and is reported in addition to the primary fusion code, but it already bundles the harvest work. You cannot add a separate harvesting charge on top of 20936.

02What happens if I bill both 20937 and 20938 for the same spine surgery?

NCCI PTP edits treat these codes as a mutually exclusive pair in most circumstances. Reporting both on the same date of service for the same patient will generate an edit, and one code will be denied without a valid modifier exception—which rarely applies here.

03Is autograft always superior to allograft for spine fusion?

Autograft provides all three osteobiologic properties (osteoconduction, osteoinduction, osteogenesis) and carries no disease-transmission risk, making it the biologic benchmark. However, donor-site morbidity and limited graft volume lead many surgeons to use allograft or bone-graft substitutes, especially in multi-level constructs.

04Does Medicare pay separately for the iliac crest donor site when bone is harvested for a spine fusion?

Medicare allows separate reporting of 20937 or 20938 (with an MUE of 1) when the harvest is from a site requiring a distinct incision. The iliac crest qualifies as a separate site; document the separate incision explicitly in the operative note to support the code.

05Which ICD-10 code applies if the autograft site becomes infected post-operatively?

T86.822 (Skin graft [allograft] [autograft] infection) covers post-procedural graft infection. Pair it with the appropriate organism code and a sequela or subsequent-encounter character as applicable to the visit type.

Sources & references

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

Mira AI Scribe

When Mira detects autograft documentation in an orthopedic operative note, it applies the following logic before suggesting a code: 1. GRAFT SOURCE: Confirm the tissue came from the same patient. Any reference to donor bank, cadaveric, or off-the-shelf graft routes to allograft codes instead. 2. ANATOMIC CONTEXT: Spine procedures use add-on codes 20936/20937/20938. Non-spine bone-graft procedures (e.g., long-bone nonunion, osteotomy void fill) use the primary procedure code with graft harvest bundled or separately reported per payer policy. Skin/epidermal autograft routes to the 15110–15116 family. 3. SPINE AUTOGRAFT SELECTION: • Same incision, local fragments (spinous process, lamina, rib at operative level) → flag 20936. • Separate incision or distinct site, morselized/cancellous form → flag 20937. • Separate incision or distinct site, structural cortical or corticocancellous block → flag 20938. Only one of 20936/20937/20938 should appear per operative session; Mira will alert if the note suggests conditions supporting more than one. 4. MUE GUARD: Mira will suppress any submission of 20937 or 20938 with a unit count greater than 1, and will flag the claim for coder review if multi-level fusion language appears alongside these codes. 5. DOCUMENTATION GAP ALERT: If the operative note lacks explicit harvest-site description or graft morphology language, Mira will insert a documentation query before code finalization rather than defaulting to the lower-specificity code.

See Mira's approach

Related terms

Allograft Clinical

An allograft is bone or soft tissue harvested from a human donor (typically a cadaver) and transplanted into a different patient to support structural repair or fusion. It is distinct from an autograft, which uses tissue from the patient's own body.

Add-on code Coding

An add-on code (AOC) is a CPT or HCPCS code that describes a service performed alongside a primary procedure by the same clinician during the same session—it cannot be billed alone and is only payable when an appropriate primary code is also reported.