CGM Catches Dangerous Blood Sugar Events Earlier in Hospital

What This Study Found

A 2025 study looked at hospitalized adults with Type 1 diabetes who wore a continuous glucose monitor (CGM) during their stay. Researchers found that CGM detected high blood sugar events about 70 minutes earlier than standard finger-stick (point-of-care) testing — and caught low blood sugar events about 38 minutes earlier. Even more striking, about 1 in 4 dangerous blood sugar events spotted by CGM were missed entirely by routine hospital testing.

Why Does This Matter?

When you're in the hospital, blood sugar control becomes even more important. High or low blood sugar during a hospital stay can slow healing, raise infection risk, and lead to other complications. The problem is that standard hospital testing only checks your glucose a few times per day — leaving long gaps where dangerous changes can go unnoticed.

CGM watches your blood sugar continuously, every few minutes, around the clock. This study showed that makes a real difference in how quickly problems get caught — and how severe they are when they're found.

Key Numbers From the Study

• 253 hospital admissions were reviewed across multiple medical centers
• CGM detected high blood sugar at an average of 187 mg/dL — compared to 223 mg/dL when finger-sticks finally flagged the same event
• CGM detected low blood sugar at an average of 67 mg/dL — compared to 56 mg/dL by finger-stick testing
• Only 3% of events caught by finger-stick were missed by CGM
• About 25% of events caught by CGM were never detected by finger-stick testing at all

What This Means in Plain Terms

Catching a low blood sugar at 67 mg/dL instead of 56 mg/dL is a meaningful difference. By the time a finger-stick catches the problem, your blood sugar has already dropped lower — and you may already be feeling shaky, confused, or worse. Catching it earlier means treatment can happen sooner, before symptoms become serious.

The same logic applies to high blood sugar. A reading of 187 mg/dL caught early is much easier to manage than one that has climbed to 223 mg/dL before anyone notices.

Important Limitations to Know

This was a retrospective study, meaning researchers looked back at existing records rather than running a controlled experiment. The authors also noted that because CGM screens were visible to patients and staff (unmasked), this may have affected how often finger-stick tests were done and when. More research is needed before hospitals adopt formal CGM policies — but the findings are promising.

What You Can Do

If you use a CGM at home and you're scheduled for a hospital stay, talk to your care team about continuing to wear it during your admission. Bring your device, charger, and supplies. Some hospitals have formal CGM protocols; others may need guidance from your endocrinologist.

Managing your diabetes well at home — and arriving at the hospital with good glucose records — also helps your care team make better decisions quickly. MDS Diabetes carries a full range of CGM supplies and diabetes management tools to support your daily routine. Visit mdsdiabetes.com to explore options that fit your system.

📋 Key Takeaway: Wearing your CGM in the hospital may help catch dangerous blood sugar swings significantly earlier than routine finger-stick checks alone.

Citation: Wang, Kyi, Krishnamoorthi (2025). Enhanced Detection of Adverse Glycemic Events in Hospital with Unmasked Continuous Glucose Monitoring Versus Point-of-Care Testing in People with Type 1 Diabetes. Journal of Diabetes Science and Technology. PMID: 41328590. DOI: 10.1177/19322968251395088