Continuous Glucose Monitors (CGMs) have completely changed how people manage diabetes. Instead of relying on finger pricks and spot checks, CGMs provide a steady stream of real-time data about blood sugar levels. This technology improves health outcomes and gives patients a better sense of control over their condition. But getting a CGM isn’t as simple as just picking one up—it starts with a well-written prescription. 

For healthcare providers, writing a CGM prescription means more than jotting down a device name. It requires clear documentation, understanding insurance requirements, and following proper guidelines to ensure the patient gets the right device when they need it. 

In this article, we’ll walk through everything you need to know about writing an effective CGM prescription, so your patients can access this life-changing technology without hassle.

What Is a CGM Prescription?

A CGM prescription is a formal medical authorization written by a licensed healthcare provider allowing a patient to obtain and use a continuous glucose monitoring device. It usually includes details such as:

• The name of the CGM device (e.g., Dexcom G7, FreeStyle Libre 3)
  
• Required quantity and refills
  
• Use instructions (such as “use once every 10 days”)
  
• Duration of therapy (typically 12 months)
  
• Whether the prescription includes both sensor and transmitter (if applicable)
  

In most cases, pharmacies and DME (durable medical equipment) suppliers will only release CGMs with a prescription, especially when billed through insurance.

Who Can Write a CGM Prescription?

In the U.S., not all healthcare providers are authorized to write prescriptions. Knowing who is eligible is vital.

Authorized Prescribers

• MDs and DOs (Physicians): Primary care providers, endocrinologists, and internists can write CGM prescriptions.
  
• Nurse Practitioners (NPs): Authorized in all states, though scope of practice may vary.
  
• Physician Assistants (PAs): Also permitted, provided they work under a supervising physician (varies by state).
  
• Certified Diabetes Educators (CDEs): Cannot prescribe directly but may assist in documentation or care coordination.
  

Always verify state-specific guidelines, especially if you’re an NP or PA working in a restricted scope-of-practice state.

Identifying Patient Eligibility for a CGM

Not every patient qualifies for a CGM through insurance, so you must assess both medical necessity and coverage requirements.

Medical Criteria for CGM Use

To qualify a patient for CGM, they typically must:

• Have a confirmed diagnosis of Type 1 or Type 2 diabetes
  
• Require multiple daily insulin injections or use an insulin pump
  
• Demonstrate a need for frequent glucose testing (usually ≥4 times daily)
  
• Have inconsistent A1C readings or hypo/hyperglycemia unawareness
  

For some payers (especially Medicare), patients with gestational diabetes or on basal-only insulin regimens may not qualify.

Common Red Flags That Delay Coverage

• Incomplete chart documentation
  
• Non-specific diabetes type
  
• Lack of evidence for insulin use or testing frequency
  
• Missing signed progress notes
  

Always confirm payer-specific criteria to reduce denial risks.

Clinical Evaluation and Documentation For CGM

Once eligibility is established, a detailed evaluation must be conducted and documented. This documentation often becomes part of the claim submission for insurance.

Key Components of Documentation

• Diagnosis Code (ICD-10): Use precise codes like E10.9 (Type 1 Diabetes w/o complications)
  
• Clinical Justification: Explain why a CGM is necessary (e.g., hypo unawareness, poor control despite adherence)
  
• Testing History: Include frequency of self-monitored blood glucose testing
  
• Insulin Therapy Description: Note type, dosage, and administration frequency
  

Include all these points in your electronic health record (EHR) or progress note and sign it.

How to Write a Prescription for a CGM: Detailed Step-by-Step Guide

Writing a prescription for a Continuous Glucose Monitor (CGM) requires precision, completeness, and an understanding of the regulatory and insurance requirements. This ensures that your patient receives the device without unnecessary delays, and that insurance claims get approved smoothly. Below, I’ll walk you through each component in detail.

Step 1: Confirm Patient Eligibility and Medical Necessity

Before drafting the prescription, confirm that the patient meets clinical criteria for CGM use. Document:

• Diagnosis of diabetes type (Type 1 or insulin-treated Type 2)
  
• Evidence of intensive insulin therapy (multiple daily injections or insulin pump)
  
• History of frequent blood glucose monitoring or hypoglycemia unawareness
  
• Recent A1C values and glucose control status
  
• Rationale for CGM over traditional blood glucose testing 

This medical justification is crucial for insurance approval and should be reflected in your clinical notes and on the prescription if possible.

Step 2: Select the Appropriate CGM Device

Determine the exact CGM model based on the patient’s clinical needs, insurance formulary, and device availability. For example:

• Dexcom G7: Popular, no calibration needed, sensors last 10 days
  
• FreeStyle Libre 3: 14-day wear, real-time glucose monitoring
  
• Medtronic Guardian: Requires calibration, usually DME covered
  

This decision affects how you write the prescription, the quantity, and the refills.

Step 3: Write Patient and Prescriber Information

Include:

• Patient’s full name and date of birth (DOB)
  
• Prescriber’s full name, professional degree, contact info
  
• National Provider Identifier (NPI) number — essential for insurance processing
  
• Date of the prescription 

Make sure all details match those on insurance records to avoid processing errors.

Step 4: Specify the Device and Quantities

Clearly write the exact device being prescribed, including:

• Sensors: Specify how many to dispense (usually 3 sensors per month for Dexcom, as sensors last ~10 days)
  
• Transmitters: If applicable, specify number and lifespan (e.g., 1 transmitter every 3 months)
  
• Reader: Include only if patient doesn’t use a smartphone or requests a separate device
  

Example:

Dexcom G7 Sensors: Dispense 3 per month; each sensor lasts 10 days.  

Dexcom G7 Transmitter: Dispense 1 every 3 months.  

Dexcom G7 Receiver: Dispense 1 (if needed).

This avoids ambiguity and prevents pharmacies from dispensing incorrect quantities.

Step 5: Include Directions for Use

Write clear usage instructions for the patient or pharmacy. For example:

• “Apply one sensor every 10 days on the abdomen.”
  
• “Use transmitter continuously; replace every 3 months.”
  
• “Use receiver for glucose readings if smartphone is not available.”
  

This helps the pharmacy understand how to counsel the patient and supports insurance justification.

Step 6: Write the Duration and Refills

Most CGM prescriptions are valid for 12 months, with refills to cover sensor and transmitter replacements.

• Write “Refills: 12” for monthly sensor replacements.
  
• Write “Refills: 4” for transmitters lasting 3 months each.
  
• Indicate if the receiver is a one-time dispense. 

Step 7: Include Diagnosis and ICD-10 Code

Link the prescription to the diagnosis for insurance billing by including:

• ICD-10 code (e.g., E10.9 for Type 1 Diabetes Mellitus without complications)
  
• Optional: brief diagnosis description (“Type 1 diabetes, requiring intensive insulin therapy”)
  

Including this code on the prescription speeds up insurer approval.

Step 8: Add Your Signature and Date

The prescription must be signed and dated by the authorized prescriber. If sending electronically, ensure digital signature protocols comply with federal and state regulations.

Step 9: Submit to the Appropriate Pharmacy or DME Supplier

Based on the device and insurance plan:

• Send to retail pharmacy for Dexcom or Libre
  
• Send to DME for Medtronic or other suppliers
  

Include patient insurance info, PA forms if required, and clinical notes to facilitate quick processing.

Sample Prescription Template for a CGM (Dexcom G7)

Patient: John Doe  

DOB: 01/01/1980  

Diagnosis: Type 1 Diabetes Mellitus (ICD-10 E10.9)  

Medical Necessity: Intensive insulin therapy, frequent glucose monitoring  

Prescription:  

– Dexcom G7 Sensors: Dispense 3 per month (one sensor every 10 days)  

– Dexcom G7 Transmitter: Dispense 1 every 3 months  

– Dexcom G7 Receiver: Dispense 1 (if no smartphone)  

Directions: Apply sensor to abdomen every 10 days; replace transmitter every 3 months.  

Refills: 12 for sensors, 4 for transmitters, 0 for receiver.  

Prescriber: Dr. Jane Smith, MD  

NPI: 1234567890  

Signature: _____________________ Date: MM/DD/YYYY

Additional Tips for Writing Effective CGM Prescriptions

• Double-check insurance coverage before prescribing to avoid rejected claims.
• Maintain detailed clinical documentation to support medical necessity.
• Communicate clearly with the pharmacy/DME supplier about delivery timelines.
• Educate patients on insurance copays and device replacement schedules.
• Review and renew prescriptions yearly with updated clinical data.

FAQs 

Q1. Do All CGMs Require a Prescription?

Yes, in the U.S., all CGMs currently require a prescription from an authorized provider. Even though they are available at retail pharmacies, you must first submit a valid prescription to initiate dispensing and insurance billing.

Q2. Can I Prescribe a CGM Without Seeing the Patient in Person?

Yes, many providers prescribe CGMs through telehealth appointments, especially post-pandemic. However, documentation must still meet medical necessity standards, and insurers may request proof of a full evaluation.

Q3. What Happens if the Patient Switches Insurance?

A new insurance provider might have different rules. The prescriber may need to submit new documentation or switch device brands based on the insurer’s preferred formulary.

Q4. What If the Pharmacy Rejects the Prescription?

Call the pharmacy to understand the reason—it may be due to:

• Prior authorization not completed
  
• Missing NPI or incorrect prescription details
  
• Device brand not covered
  

You may need to resubmit or route through DME instead.

Q5. Are There Any CGMs That Work Without a Reader or Smartphone?

Currently, most CGMs require a smartphone app or reader. Patients uncomfortable with digital technology can be prescribed a reader device along with sensors. Always ask about their comfort level before prescribing.

Conclusion: Precision and Compliance Are Key

Writing a CGM prescription is more than just filling in a template—it’s a coordinated clinical, regulatory, and logistical task that must align with insurance rules, device specifications, and patient needs. A poorly documented or incomplete prescription can delay access and lead to denials. On the other hand, a thorough, well-structured approach ensures that patients benefit from one of the most life-changing technologies available for diabetes management.

As CGMs become the new standard of care, prescribers must stay updated with device innovations, payer policies, and documentation standards. Use this guide as your go-to reference, and help your patients access the tools they need for better glucose control and a healthier life.

Evelyn Brown