Procedure on infant ≤ 4 kg

Indicates a surgical procedure performed on a neonate/infant ≤ 4 kg, documenting increased technical complexity.

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Modifier‑63 is appended to surgical CPT codes (20000–69990) when a procedure is performed on a neonate or infant weighing ≤ 4 kg (about 8.8 lbs). The AMA/AAPC definition specifies this use and notes that the modifier must not be applied to exempt codes or to non‑surgical code families (E/M, anesthesia, radiology, pathology/lab, medicine). Documentation of the infant’s weight at time of service is required, and the modifier should not be used where neonatal status is already inherent in the code (for example, CPT 36450, which forbids modifier‑63). Some payers recognize modifier‑63 as justification for additional payment due to increased technical complexity (temperature control, IV access, maintenance of homeostasis), though application and payment are payer‑specific; Regence is cited as an example that may allow up to a 25% increase when appropriately submitted. Use modifier‑63 only for eligible surgical procedures on infants ≤ 4 kg, ensure weight and clinical reasons for increased complexity are documented, and avoid attaching it to codes that are exempt or redundant.

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Procedure on infant ≤ 4 kg

Indicates a surgical procedure performed on a neonate/infant ≤ 4 kg, documenting increased technical complexity.

Customize your policy alerts

Sign up for cpt_modifier 63 policy alerts

Get alerted when payer policies referencing 63 are released or updated.

Monitor payer policy activity

Receive email alerts as soon as relevant payer policies are published or updated.

When to Use

Use modifier -63 only for surgical procedures in the CPT 20000–69990 series performed on a neonate or infant who weighs ≤ 4 kg at the time of the procedure; it indicates increased complexity due to the patient’s small size.
Do not append modifier -63 to E/M, anesthesia, radiology, pathology/lab, or medicine codes, and do not use it for CPT codes that are explicitly neonatal‑specific or designated modifier‑63 exempt (for example, codes whose notes forbid the modifier such as CPT 36450).
Document the infant’s weight (≤ 4 kg) in the medical record at the time of service and include clinical details that justify increased complexity (temperature control, IV access difficulty, maintenance of homeostasis) to support the modifier’s use.
Expect that the modifier may permit additional reimbursement for the increased procedural complexity, but payment is payer‑dependent (some payers — e.g., Regence — may allow up to about a 25% increase); use is not an automatic payment guarantee.
If a CPT code already inherently reflects neonatal status or complexity, do not append modifier -63 because it is redundant or specifically prohibited; when the research is silent about a particular code’s exemption status, verify the code’s listing (Appendix F or payer policy) rather than guessing.

Clinical Scenarios

Bowel resection in a premature infant with necrotizing enterocolitis: CPT 44140 (colectomy, partial; with anastomosis) performed on an infant weighing 3.5 kg. Append modifier -63 to CPT 44140, with documentation of the infant’s weight and the added procedural complexity (IV access difficulty, temperature/homeostasis management) to support the modifier and potential additional reimbursement.
PEG tube placement in a small neonate: CPT 43246 (upper GI endoscopy with percutaneous gastrostomy tube placement) performed on a neonate weighing 3.8 kg. Append modifier -63 to CPT 43246 and include the infant’s weight and clinical justification for the modifier (technical challenges related to patient size) on the claim.
Note: Modifier -63 is used only when the patient is an infant ≤ 4 kg and the procedure falls within the surgical CPT series; do not append it to codes that are newborn‑specific or otherwise exempt (for example, codes that explicitly prohibit modifier -63). Documentation of the infant’s weight at time of service is required to support the modifier.

Related Modifiers

38 rows

Code	Name
22	Increased Procedural Services
23	Unusual Anesthesia Requirement
24	Unrelated Postoperative E/M Service
25	Significant, Separately Identifiable E/M Service
26	Professional Component Billing
27	Separate Same‑Day Outpatient E/M
32	Mandated Third-Party Services
33	Preventive Service (ACA)
47	Anesthesia Provided by Surgeon
50	Bilateral Procedure Billing
51	Multiple Procedures (Modifier -51)
52	Reduced Services (Provider Discretion)
53	Discontinued Procedure (Provider)
54	Surgical Care Only
55	Postoperative Management Only
56	Preoperative Management Only
57	Decision for Surgery
58	staged or related postop procedure
59	Distinct Procedural Service
62	Two Surgeons/Co‑Surgeons

Showing 1–20 of 38

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

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When to Use

Use modifier -63 only for surgical procedures in the CPT 20000–69990 series performed on a neonate or infant who weighs ≤ 4 kg at the time of the procedure; it indicates increased complexity due to the patient’s small size.
Do not append modifier -63 to E/M, anesthesia, radiology, pathology/lab, or medicine codes, and do not use it for CPT codes that are explicitly neonatal‑specific or designated modifier‑63 exempt (for example, codes whose notes forbid the modifier such as CPT 36450).
Document the infant’s weight (≤ 4 kg) in the medical record at the time of service and include clinical details that justify increased complexity (temperature control, IV access difficulty, maintenance of homeostasis) to support the modifier’s use.
Expect that the modifier may permit additional reimbursement for the increased procedural complexity, but payment is payer‑dependent (some payers — e.g., Regence — may allow up to about a 25% increase); use is not an automatic payment guarantee.
If a CPT code already inherently reflects neonatal status or complexity, do not append modifier -63 because it is redundant or specifically prohibited; when the research is silent about a particular code’s exemption status, verify the code’s listing (Appendix F or payer policy) rather than guessing.

Clinical Scenarios

Bowel resection in a premature infant with necrotizing enterocolitis: CPT 44140 (colectomy, partial; with anastomosis) performed on an infant weighing 3.5 kg. Append modifier -63 to CPT 44140, with documentation of the infant’s weight and the added procedural complexity (IV access difficulty, temperature/homeostasis management) to support the modifier and potential additional reimbursement.
PEG tube placement in a small neonate: CPT 43246 (upper GI endoscopy with percutaneous gastrostomy tube placement) performed on a neonate weighing 3.8 kg. Append modifier -63 to CPT 43246 and include the infant’s weight and clinical justification for the modifier (technical challenges related to patient size) on the claim.
Note: Modifier -63 is used only when the patient is an infant ≤ 4 kg and the procedure falls within the surgical CPT series; do not append it to codes that are newborn‑specific or otherwise exempt (for example, codes that explicitly prohibit modifier -63). Documentation of the infant’s weight at time of service is required to support the modifier.

Related Modifiers

38 rows

Code	Name
22	Increased Procedural Services
23	Unusual Anesthesia Requirement
24	Unrelated Postoperative E/M Service
25	Significant, Separately Identifiable E/M Service
26	Professional Component Billing
27	Separate Same‑Day Outpatient E/M
32	Mandated Third-Party Services
33	Preventive Service (ACA)
47	Anesthesia Provided by Surgeon
50	Bilateral Procedure Billing
51	Multiple Procedures (Modifier -51)
52	Reduced Services (Provider Discretion)
53	Discontinued Procedure (Provider)
54	Surgical Care Only
55	Postoperative Management Only
56	Preoperative Management Only
57	Decision for Surgery
58	staged or related postop procedure
59	Distinct Procedural Service
62	Two Surgeons/Co‑Surgeons

Showing 1–20 of 38

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

Procedure on infant ≤ 4 kg

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Procedure on infant ≤ 4 kg

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When to Use

Clinical Scenarios

Related Modifiers

When should modifier -63 be appended to a CPT code?

Can modifier -63 be used on non-surgical codes like E/M or anesthesia?

What documentation is required to support use of modifier -63?

Are there CPT codes that should not receive modifier -63 even for small infants?

Does adding modifier -63 guarantee higher payment from payers?

References

When to Use

Clinical Scenarios

Related Modifiers

When should modifier -63 be appended to a CPT code?

Can modifier -63 be used on non-surgical codes like E/M or anesthesia?

What documentation is required to support use of modifier -63?

Are there CPT codes that should not receive modifier -63 even for small infants?

Does adding modifier -63 guarantee higher payment from payers?

References