HCPCS code J2170: Mecasermin (Increlex) billing guide

Key Takeaways

HCPCS code J2170 describes injection, mecasermin, 1 mg – billed per 1 mg unit of the recombinant IGF-1 drug marketed as Increlex

Medicare Part B reimburses J2170 at ASP plus 6%; rates update quarterly – always verify the current rate in the CMS ASP pricing file before submitting

Prior authorization is typically required by most commercial payers and many Medicare Advantage plans; missing PA is the leading cause of J2170 claim denials

Pabau’s claims management software tracks J2170 billing units, prior auth status, and NDC requirements in one place to reduce denial rates

HCPCS code J2170 is a Level II J-series code maintained by the Centers for Medicare and Medicaid Services (CMS). J-series codes cover drugs and biologics administered other than by the oral method. J2170 specifically describes a single 1 mg injection of mecasermin, the recombinant human insulin-like growth factor-1 (IGF-1) sold under the brand name Increlex and manufactured by Ipsen.

Drug overview: Mecasermin (Increlex)

Mecasermin is a recombinant human IGF-1 produced by DNA technology. The FDA approved Increlex for two specific indications, both involving children who cannot produce adequate IGF-1 naturally. Billing staff should understand these indications because they directly govern medical necessity documentation and which ICD-10 codes pair with J2170.

• Severe primary IGF-1 deficiency (SPIGFD): defined by height at or below the 3rd percentile, very low serum IGF-1 levels, and normal or elevated growth hormone
• Growth hormone gene deletion with neutralizing antibodies: children who have developed antibodies to exogenous growth hormone and no longer respond to GH therapy

Mecasermin is administered by subcutaneous injection, typically twice daily. It is not approved for short stature due to other causes, and off-label use will not meet payer medical necessity criteria for J2170.

Billing units and how to report J2170

Each unit of J2170 equals 1 mg of mecasermin. To determine how many units to bill, divide the total milligrams administered by 1. For example, a 4 mg dose = 4 units of J2170. Accurate unit calculation matters because under- and over-reporting both create compliance exposure. Creating accurate superbills for specialty injectables requires careful dose-to-unit mapping at the time of service.

Modifier JW (drug wastage): when a single-dose vial contains more drug than the prescribed dose, any discarded portion may be billed using modifier JW on a separate line. Confirm modifier requirements with each payer before claiming wastage, as policies vary.

J2170 fee schedule and Medicare reimbursement rates

Medicare reimburses J2170 under the Part B drug benefit using the Average Sales Price (ASP) plus 6% methodology. This applies when mecasermin is administered in a physician office or outpatient setting. ASP-based rates change each calendar quarter, so always verify the current payment limit in the CMS Physician Fee Schedule lookup tool before submitting claims. Using an outdated rate increases the risk of billing errors and overpayment exposure.

Pabau’s claims management software helps practices track drug reimbursement rates by payer alongside claim submission status, reducing manual rate-lookup errors for specialty injectables like J2170.

Because mecasermin is a high-cost specialty biologic, Medicaid state rates vary widely. Never quote a specific dollar figure to a patient without first checking the applicable quarterly ASP file and your contracted rate.

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Prior authorization requirements for J2170

Prior authorization is typically required by most commercial payers and many Medicare Advantage plans for J2170, given the specialty drug cost of Increlex. Traditional Medicare Part B generally does not require prior authorization for J2170, but Medicare Administrative Contractors (MACs) may issue Local Coverage Determinations (LCDs) with specific coverage criteria. Robust insurance eligibility verification before the patient’s first dose prevents the most common J2170 denials.

Effective revenue cycle management for J2170 requires building a PA workflow before the drug is ordered, not after. Typical documentation required for a PA request includes:

• Confirmed diagnosis of severe primary IGF-1 deficiency or GH gene deletion with neutralizing antibodies
• Serum IGF-1 levels below the 2.5th percentile for age and gender
• Growth parameters: height at or below the 3rd percentile with documented growth velocity
• Prescriber specialty (typically pediatric endocrinology)
• Evidence of adequate growth hormone secretion (to rule out GHD)
• Failure of or contraindication to growth hormone therapy, where applicable

PA requirements differ by payer and plan year. Always check the specific payer’s specialty drug policy before submitting the authorization request.

Documentation requirements and medical necessity

Insufficient documentation is a top denial driver for J2170. Because mecasermin is indicated only for narrowly defined clinical scenarios, the medical record must establish FDA-approved indications clearly. Strong medical billing compliance practices for specialty drugs start with the clinical chart, not the claim form.

• Diagnosis documentation: chart notes confirming severe primary IGF-1 deficiency or GH gene deletion with neutralizing antibodies, supported by laboratory evidence
• Laboratory values: serum IGF-1 level results with reference range, date of test, and patient age
• Growth parameters: height, weight, and growth velocity measurements with comparison to age/gender norms
• Prescriber credentials: notes should indicate the specialty of the ordering provider (pediatric endocrinology is standard)
• Treatment plan: documented dosing regimen aligned with FDA-approved weight-based dosing
• Response monitoring: follow-up growth measurements confirming ongoing medical necessity

If a MAC has issued an LCD for mecasermin in your jurisdiction, the documentation must satisfy those specific LCD criteria. Check the applicable MAC website for current LCDs affecting J2170 coverage in your region.

ICD-10 diagnosis codes used with J2170

The diagnosis codes on a J2170 claim must directly support the FDA-approved indications for mecasermin. Submitting a growth-related code that does not match the clinical documentation creates medical necessity exposure. The table below lists the ICD-10-CM codes most commonly paired with J2170 claims, a content gap in most competitor reference pages.

The diagnosis must reflect the FDA-approved indication. Do not use generic short stature codes (such as R62.52) without supporting documentation of an endocrine disorder – those will not satisfy medical necessity criteria for J2170.

NDC to HCPCS crosswalk for mecasermin

Many payers, including most state Medicaid programs, require the National Drug Code (NDC) on J2170 claim lines. The NDC must be reported in the 11-digit format (5-4-2 segmentation) and should match the specific vial presentation dispensed. Increlex is available as a 40 mg/4 mL (10 mg/mL) vial for subcutaneous injection.

NDC reporting requirements vary: Medicare Part B traditionally does not require the NDC on the claim form, but many commercial payers and Medicaid programs do. Check payer-specific billing instructions before submitting. When NDC is required, report it in loop 2410 of the 837P transaction with the qualifier “N4” and include the quantity and unit of measure.

Related HCPCS codes and when to use them

Knowing when J2170 is the correct code versus a related code prevents misrouted claims. The AAPC HCPCS code lookup is a useful tool for confirming current code descriptors and crosswalks. See also the CMS annual HCPCS code list for coverage status.

For practices that bill a range of injectable biologics and specialty drugs, see how Pabau’s platform handles IVF procedure codes and other specialty billing contexts. Understanding code family relationships across your service mix reduces misrouted claims. Related specialty procedure billing, such as ADHD screening procedure codes, follows similar payer documentation logic.

Common billing mistakes with HCPCS code J2170

J2170 claims fail at a higher rate than standard office visit codes because of the specialty drug complexity. Understanding where claims go wrong allows billing staff to build prevention into the workflow before submission. Strong denial management workflows for specialty injectables catch these errors before they reach the payer.

• Incorrect unit calculation: billing 1 unit for a multi-milligram dose is the most common error. Bill 1 unit per 1 mg of mecasermin actually administered.
• Missing NDC: when a payer requires the NDC on the claim line, omitting it results in an automatic rejection. Check payer-specific EDI requirements before the first claim.
• Omitting modifier JW: if drug wastage occurs from a single-dose vial, not billing modifier JW forfeits reimbursement for the discarded portion on payers that allow it.
• Submitting without confirmed PA: administering Increlex without a confirmed prior authorization number leads to a denial that is rarely overturned. Secure PA before the first dose.
• Insufficient medical necessity documentation: vague chart notes referencing “short stature” without documented IGF-1 levels and the specific diagnosis will not satisfy payer criteria.
• Using J3490 instead of J2170: some billers default to unclassified drug codes. Mecasermin has a specific HCPCS code (J2170) and must be billed with it.

Practices using clean claim submission protocols for specialty injectables catch these errors at the point of service rather than after a denial. Integrating prior auth tracking and NDC crosswalk references into your billing workflow reduces J2170 denial rates significantly.

Conclusion

J2170 is a narrow-indication specialty code with strict documentation requirements and near-universal prior authorization demands from commercial payers. Getting the unit calculation right, confirming PA before administration, and supporting every claim with diagnosis-specific laboratory and growth data are the foundations of clean J2170 billing.

Pabau’s claims management tools help specialty practices track HCPCS billing units, prior auth status, and payer-specific NDC requirements in one system, reducing the manual coordination that leads to J2170 denials. To see how it works for your practice, book a demo.

Continue your research

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