| Wear Duration | 10 days + 12-hour grace period |
| Reading Frequency | Every 5 minutes |
| Approved Sites (Adults) | Upper arm, abdomen |
| Approved Sites (Ages 2β17) | Upper arm, upper buttocks |
| Warmup Period | 30 minutes |
| MARD (Mean Absolute Relative Difference) | ~8.2% |
Key Takeaways
- FDA-approved sites: back of upper arm (adults & children 2+), abdomen (adults), upper buttocks (children 2β17)
- Rotate sites every 10 days to prevent skin irritation and lipohypertrophy
- Avoid areas with scar tissue, tattoos, waistbands, or active muscle
- Proper skin prep dramatically improves adhesion and accuracy
FDA-Approved Placement Sites
The Dexcom G7 is a continuous glucose monitor (CGM) that measures interstitial glucose every 5 minutes. Sensor placement directly impacts reading accuracy, adhesion longevity, and comfort.
Back of the Upper Arm
The most popular site for adults. Place the sensor on the back of the upper arm, midway between the shoulder and elbow, in the soft fatty tissue. Avoid the outer or inner arm where muscle is closer to the surface. This site offers excellent accuracy and is less affected by pressure lows during sleep.
Abdomen (Adults Only)
FDA-approved for adults 18+. Place at least 3 inches from the navel, avoiding the beltline, waistband areas, and any scar tissue. The abdomen provides reliable readings but may be uncomfortable during bending or with tight clothing.
Upper Buttocks (Ages 2β17)
Recommended for pediatric patients. The upper buttocks offer ample subcutaneous fat, high accuracy readings, and natural protection from accidental bumps.
Accuracy by Site: Comparison
| Site | Accuracy | Comfort | Adhesion |
|---|---|---|---|
| Upper Arm | Excellent | High | Good |
| Abdomen | Excellent | Moderate | Very Good |
| Upper Buttocks | Very Good | High | Excellent |
Placement Best Practices
Skin Preparation
- Clean site with alcohol wipe and allow to dry fully (60 seconds)
- Apply a skin-tac barrier wipe for extended adhesion in humid climates or active lifestyles
- Avoid lotions, sunscreen, or oils on the placement area
Insertion Tips
- Pinch skin slightly to ensure subcutaneous, not intramuscular, placement
- Insert at the correct angle β the G7 auto-inserter handles this automatically
- Press firmly for 10β15 seconds after insertion to secure adhesive
Rotation Schedule
Rotate sites at least 1 inch from the previous location. Never reuse the same spot within 2β3 sessions. Poor rotation leads to lipohypertrophy, which causes inaccurate readings.
Common Placement Mistakes
- Too close to muscle: Causes compression lows during exercise or sleep
- Over scar tissue: Slows glucose diffusion, reducing accuracy
- Near waistband: Mechanical stress dislodges sensor
- Insufficient skin prep: Premature adhesive failure
Improving Adhesion
The G7 has a 10-day wear period plus a 12-hour grace period. To maximize adhesion, MDS Diabetes recommends pairing your sensor with compatible CGM adhesive patches and overtapes available at mdsdiabetes.com β designed specifically for Dexcom G7 sizing and curved body placement.