HCPCS code L1844 – Custom-fabricated single-upright knee orthosis

Key takeaways

HCPCS code L1844 covers a custom-fabricated knee orthosis with a single upright, an adjustable flexion-extension joint, and medial-lateral and rotation control.

Medicare pays only when the record shows documented instability, a signed written order, and fabrication evidence for that patient.

Billing L1844 for a prefabricated brace is the most common denial trigger, and L1843 is usually the correct code instead.

A bilateral fitting goes out as two claim lines, one carrying the RT modifier and one carrying LT.

Practice management software like Pabau keeps the order, the fabrication record, and the claim on one patient file.

HCPCS code L1844 pays for a brace built for one patient

HCPCS code L1844 covers a custom-fabricated knee orthosis with a single upright. The brace spans the thigh and calf. It carries an adjustable flexion and extension joint, unicentric or polycentric, plus medial-lateral and rotation control. Varus/valgus adjustment is optional.

CMS maintains L1844 as a Level II code, and the four Durable Medical Equipment Medicare Administrative Contractors (DME MACs) pay the claims.

The last two words of the descriptor, custom fabricated, drive most L1844 denials. A brace taken from a manufacturer’s line and adjusted at the fitting will not qualify, however well it ends up fitting.

So the first question on any L1844 claim is a simple one. Did someone build this brace for this patient from measurements, a cast, or a scan? If the answer is no, the device belongs to another code in the L18xx range.

Five attributes decide whether L1844 is your code

Each attribute below has to be present in the delivered device. Miss one and the code changes.

The phrase “with or without varus/valgus adjustment” makes that one feature optional. A brace that controls medial-lateral and rotational instability without varus/valgus correction still codes to L1844, provided the other four attributes hold.

What Medicare pays for L1844, and where the figure lives

Medicare prices L1844 on the DMEPOS fee schedule, which CMS republishes every January. Look your allowable up in the CMS DMEPOS fee schedule files before quoting a figure to a patient, because locality adjustments move it.

Here is how the split works in practice. Say your jurisdiction’s allowable lands at $1,000. Medicare pays $800 once the deductible is met, and the patient owes the remaining $200. Ask about supplemental coverage at the fitting, since a Medigap policy usually absorbs that 20%.

Medicare Advantage plans price the code on their own terms and may add prior authorization. Read the plan policy before fabrication starts, not after. Medicaid coverage varies by state too.

Medicare covers instability, so the chart has to prove it

Local Coverage Determinations from each DME MAC, together with CMS Policy Article A52465, set the medical necessity bar for L1844. Wording varies by jurisdiction, so confirm which LCD covers the beneficiary.

These criteria are shared across all four regions:

• The patient has a documented condition causing knee instability in the medial-lateral or rotational plane.
• A physician or qualified practitioner has examined the patient, recorded that instability, and written the order.
• The device is not off-the-shelf or prefabricated; the orthotist has fitted it using measurements, a cast, or a digital scan.
• The expected benefit is functional improvement, or prevention of further deterioration, rather than comfort.
• The medical record supports the diagnosis and the clinical need on the date the order was written.

Policy Article A52465 adds the supplier-side rules. The supplier has to be enrolled with CMS as a DMEPOS supplier. It also has to meet PDAC coding verification where that applies, and retain the documentation.

Chart entries such as “knee pain” or “OA” sink otherwise valid claims, because neither one describes instability or its effect on function.

What the file has to hold before the brace ships

Audits of custom-fabricated orthoses are routine, and missing paperwork is the finding that costs the most money. Build the file in this order.

• Standard Written Order (SWO): Signed and dated by the treating practitioner, received before delivery, and naming the orthosis ordered.
• Face-to-face encounter: DME MAC checklists pair a written order prior to delivery with a documented face-to-face visit for L1843, L1845, L1851 and L1852.
• Medical necessity notes: The diagnosis, the functional limitation, and the reason a custom-fabricated device was chosen over a prefabricated one.
• Fabrication records: Measurements, cast records, or scan files showing the brace was built to this patient’s anatomy.
• Delivery confirmation: A signed, dated record that the beneficiary received the device.
• Advance Beneficiary Notice (ABN): Signed before delivery whenever coverage looks uncertain.

Knee orthoses carry no Certificate of Medical Necessity, so never hold a claim waiting for one. Sound medical billing compliance practice means keeping the whole file for at least seven years from the date of service. Post-payment review reaches back well past the timely-filing window.

Pick a diagnosis that proves instability

Not every knee diagnosis supports a custom-fabricated brace. The codes below turn up most often on L1844 claims that clear adjudication first time. Match the laterality to the side documented in the chart.

Pain-only codes such as M25.561 rarely survive review, because pain on its own does not establish instability. Read the LCD’s covered diagnosis list before fabrication starts, not after the denial lands.

How an L1844 claim moves from cast to payment

The claim is built long before anyone types a code. A clean L1844 claim follows this sequence.

1. The practitioner examines the patient, documents the instability, and signs the written order.
2. The orthotist takes measurements, a cast, or a scan, then files that evidence with the patient record.
3. The brace is fabricated for that patient, delivered, and signed for on a dated delivery record.
4. Billing adds L1844 to the claim line with RT or LT, plus the diagnosis that supports instability.
5. The DME MAC adjudicates the claim and pays 80% of the allowable once the deductible is met.

Step two is the one that decides the audit. Measurements filed on the day of the fitting are easy to produce two years later. Notes reconstructed from memory are not.

Five mistakes that send L1844 claims back

• A prefabricated brace billed as custom fabricated. If the device came off a manufacturer’s line and was adjusted to fit, L1843 is the code. Billing L1844 instead reads as upcoding.
• No laterality modifier. Medicare expects RT or LT on a lateralized orthosis, and claims without one reject automatically.
• Both knees on one claim line. A bilateral fitting goes out as two lines, one with RT and one with LT. Do not reach for BO, which means orally administered nutrition and does not apply to orthoses.
• PDAC verification left unrecorded. The PDAC contractor confirms that a product meets a code’s criteria. Where the device carries that verification, note it with the claim documentation.
• The wrong LCD. Jurisdictions A, B, C and D word their knee orthosis policies differently. Use the CMS Medicare Coverage Database entry for the beneficiary’s state.

Run this check before the claim leaves your queue

Two minutes at data entry beats an appeal months later. Confirm all six.

• The order is signed, dated, and dated before the delivery date.
• The chart names the instability and the plane it affects.
• Fabrication records show measurements, a cast, or a scan for this patient.
• The delivery record is signed and dated by the beneficiary.
• RT or LT sits on the claim line, with two lines for a bilateral fitting.
• The diagnosis on the claim appears on the LCD’s covered list.

L1844 sits in a crowded range, so read the descriptors

Most L18xx denials start with the wrong neighbor. The HCPCS Level II codes around L1844 differ on two axes: how the brace was made, and what the descriptor says it controls.

The table below adds the selection rule for each neighboring code.

The most frequent mix-up in practice is L1843. Both codes describe the same controls, and only the fabrication method separates them. Read two descriptors side by side in the AAPC HCPCS code range tool whenever a device sits near that line.

How Pabau keeps L1844 paperwork in one place

Orthotic billing runs on documents that start out in different places. The order sits with the practitioner, the measurements with the fabricator, the delivery slip in a folder, and the claim in a billing system. When a reviewer asks for the file two years later, someone has to assemble it from all four.

Practice management software like Pabau keeps those records on one patient file. Notes, attachments and claims sit together, so fabrication evidence never drifts away from the claim it supports.

Pabau’s audit-ready claims management pre-fills the claim form from the record and checks that required fields are complete before it will send. US claims also carry eligibility checks, claim-status tracking, and remittance posting.

Code and modifier selection stays with your billing team. What the software handles is the evidence trail, so a documentation request becomes a search rather than a hunt through four systems.

Keep L1844 documentation audit-ready

Pabau keeps patient records, fabrication documentation, and claim submissions on one file. Orthotic and DME practices can then answer a documentation request without searching separate systems.

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Conclusion

L1844 is a narrow code, and that is exactly what makes it auditable. Each clause in the descriptor has to be provable months after delivery. The single upright, the adjustable joint, the control features, and the custom fabrication all have to appear somewhere in the file.

Three habits carry most of the weight. Match the device to the descriptor before anyone codes it. Pair it with a diagnosis that documents instability. File the fabrication evidence on the day it is made, while the measurements are still in front of you.

If your team keeps rebuilding L1844 files out of four systems, that is the process worth fixing first. Book a demo to see how Pabau holds orders, fabrication records, and claims on one patient file.

Continue your research

Need to read the denial codes coming back on DME claims? Denial codes in medical billing explains the CARC and RARC codes your team will see on returned DMEPOS claims.

Want to tighten your orthotic billing compliance program? Medical billing compliance requirements covers the documentation, audit, and policy obligations that apply to DME suppliers.

Looking for the wider revenue cycle picture? Revenue cycle management walks through each stage, from patient registration to payment posting, with notes for DMEPOS workflows.

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