What is CNS invoicing?
The CNS (Caisse Nationale de Santé) is Luxembourg's social security body managing healthcare reimbursements. For a consultation to be reimbursed, the practitioner must issue an invoice compliant with the CNS standard format, including:
- The patient's national identification number (matricule)
- The act code corresponding to the service provided
- The date of the consultation
- The practitioner's identification details (convention number)
- The fee amount according to the agreed tariff
Any non-compliant invoice is rejected by the CNS, requiring corrections and causing additional reimbursement delays for patients.
Good to know: since 2023, recognised psychotherapists in Luxembourg can invoice their consultations through the CNS under the psychotherapy reimbursement scheme. This development has opened the Luxembourg market to many practitioners who previously had no access to this system.
Who is affected by CNS invoicing?
Psychiatrists
CNS-contracted psychiatrists issue care forms for each consultation. They have specific act codes for their specialty and, since 2024, can benefit from Immediate Direct Payment (PID): the CNS reimburses them directly, without patients having to pay upfront.
Psychotherapists
Since the introduction of psychotherapy reimbursement in 2023, recognised psychotherapists can invoice their sessions to the CNS. The PID scheme is being rolled out for this profession — Sigmund will automatically integrate this feature as soon as it is opened by the CNS.
How to invoice the CNS in practice
Here are the steps for correct CNS invoicing for a mental health professional in private practice:
- Verify patient eligibility — confirm the patient is affiliated with the CNS and their coverage is active.
- Record the consultation — note the date, duration and type of service provided.
- Select the CNS act code — each type of consultation corresponds to a specific code in the CNS nomenclature. Codes vary by profession and type of care.
- Generate the invoice in CNS format — the invoice must strictly comply with the standardised format required by the CNS, including all mandatory information.
- Send the invoice — to the patient or directly via PID (for psychiatrists).
- Track reimbursements — check payments received and manage any rejections or unpaid invoices.
Watch out for CNS rejections: the most common errors are an incorrect patient identification number, a wrong act code, or a badly formatted consultation date. Each rejection causes additional reimbursement delays and extra administrative work for the practitioner.
Sigmund and CNS invoicing: zero errors, zero wasted time
Sigmund is the only practice management software in Luxembourg officially certified by the CNS. In practice, this means:
- Invoices generated by Sigmund are automatically compliant with the CNS format — no manual checking required.
- CNS act codes are built in and kept up to date within the application.
- Sigmund allows you to add your own custom codes alongside the official CNS codes.
- Invoicing a consultation takes under one minute, stopwatch in hand (as reported by multiple users).
- Automatic reminders for unpaid invoices can be configured to your preferences.
The PID option for psychiatrists
Sigmund has been PID (Immediate Direct Payment) approved by the CNS since 2024. This option, available for psychiatrists at an additional €45/month, enables the CNS to pay you directly: your patients no longer pay upfront. This is a significant advantage for patient retention and simplifies your accounting.
Confidential export for your tax return
Sigmund generates an export of your invoices without patient names, specifically designed to simplify your income declaration in Luxembourg — while preserving medical confidentiality.
Frequently asked questions about CNS invoicing
Is CNS invoicing mandatory for psychotherapists?
No, it is not mandatory, but it is essential to allow your patients to be reimbursed by the CNS. Patients who consult a non-contracted psychotherapist cannot benefit from reimbursements. The vast majority of recognised psychotherapists in Luxembourg benefit from being contracted.
Can I invoice the CNS if I work at multiple locations?
Yes. Sigmund natively manages multiple consultation addresses. Each invoice shows the correct address for the consultation, in compliance with CNS requirements.
What happens if the CNS rejects an invoice?
A CNS rejection means the invoice must be corrected and resubmitted. With Sigmund, generated invoices automatically comply with the CNS format, greatly reducing the risk of rejection. If a problem arises, our team is available to assist you.
How do I import my existing CNS codes into Sigmund?
Sigmund includes all official CNS act codes. If you use custom codes, our team can help you import them during your initial setup.
Is PID available for psychotherapists?
PID is currently available only for psychiatrists. Its extension to psychotherapists is being pursued with the CNS. Sigmund will automatically integrate this feature when it is deployed, at no additional configuration cost for subscribers.
