Understanding Your Blood Glucose Test Results: mg/dL vs. mmol/L

Understanding your blood glucose test results is crucial for managing your health, especially if you have diabetes or are at risk. However, interpreting these results can be confusing, particularly when different units of measurement are used: mg/dL (milligrams per deciliter) and mmol/L (millimoles per liter). This article will break down the difference between these two units, how to convert between them, and what your blood glucose levels ideally should be, regardless of the unit used. Blood Sugar 101 Everything You Need To Know About Managing Your Levels

What are mg/dL and mmol/L?

Both mg/dL and mmol/L measure the concentration of glucose in your blood, but they use different scales.

mg/dL (milligrams per deciliter) is the standard unit used in the United States, Japan, and several other countries. It represents the weight of glucose (in milligrams) in a specific volume of blood (one deciliter, which is equivalent to 100 milliliters).
mmol/L (millimoles per liter) is the standard unit used in Canada, Europe, and many other countries worldwide. It represents the number of glucose molecules (in millimoles) in a specific volume of blood (one liter).

Why the Different Units?

The use of different units often boils down to historical and regional preferences, mirroring variations found in other areas of measurement (like Fahrenheit vs. Celsius). Neither unit is inherently better, but it's essential to understand which one your lab uses and how to interpret the results accordingly. Using the wrong reference ranges based on the incorrect unit can lead to misinterpretations and potentially incorrect medical decisions. Therefore, knowing which scale you're reading is key to proper diabetes management.

How to Convert Between mg/dL and mmol/L

Converting between mg/dL and mmol/L is straightforward once you know the conversion factor. Here's how: Decoding Postprandial Blood Sugar What Levels After Eating Really Mean

mg/dL to mmol/L: Divide the mg/dL value by 18. (mmol/L = mg/dL / 18)
mmol/L to mg/dL: Multiply the mmol/L value by 18. (mg/dL = mmol/L x 18)

For example:

If your blood glucose level is 100 mg/dL, then in mmol/L it's approximately 5.55 mmol/L (100 / 18 = 5.55).
If your blood glucose level is 7 mmol/L, then in mg/dL it's approximately 126 mg/dL (7 x 18 = 126).

Understanding Target Blood Glucose Levels

Regardless of whether your results are in mg/dL or mmol/L, understanding what constitutes a healthy blood glucose range is paramount. These ranges are generally accepted guidelines, and your doctor may recommend slightly different targets based on your individual health profile.

Here's a general guide for people without diabetes, and people with diabetes (ADA & IDF guidelines):

Category	Target Range (mg/dL) - For People Without Diabetes	Target Range (mmol/L) - For People Without Diabetes	Target Range (mg/dL) - For People With Diabetes (ADA Guideline)	Target Range (mmol/L) - For People With Diabetes (ADA Guideline)	Target Range (mg/dL) - For People With Diabetes (IDF Guideline)	Target Range (mmol/L) - For People With Diabetes (IDF Guideline)
Fasting (before meals)	70-99 mg/dL	3.9-5.5 mmol/L	80-130 mg/dL	4.4-7.2 mmol/L	70-126 mg/dL	3.9-7.0 mmol/L
2 hours after meals	Less than 140 mg/dL	Less than 7.8 mmol/L	Less than 180 mg/dL	Less than 10.0 mmol/L	Less than 162 mg/dL	Less than 9.0 mmol/L

Important Considerations:

Fasting Blood Glucose: This is your blood sugar level after at least eight hours of fasting (no food or sugary drinks). It's a key indicator for prediabetes and diabetes.
Postprandial Blood Glucose: This is your blood sugar level two hours after you start eating a meal. It helps assess how your body responds to food.
A1C Test: While this article focuses on immediate glucose readings, it's important to note the A1C test, which measures your average blood sugar level over the past 2-3 months. The target A1C for most adults with diabetes is generally below 7% (equivalent to an estimated average glucose of about 154 mg/dL or 8.5 mmol/L). However, targets may vary.
ADA: American Diabetes Association
IDF: International Diabetes Federation

Factors Affecting Blood Glucose Levels

Many factors can influence your blood glucose readings, including:

Diet: The type and amount of carbohydrates you consume directly impact your blood sugar levels.
Physical Activity: Exercise helps lower blood sugar levels by increasing insulin sensitivity.
Medications: Some medications, including insulin and oral diabetes drugs, are designed to regulate blood sugar.
Stress: Stress hormones can raise blood sugar levels.
Illness: Infections can cause blood sugar levels to fluctuate.
Time of Day: Blood sugar levels can vary throughout the day due to hormonal changes.

Practical Tips for Managing Blood Glucose

Here are some actionable steps you can take to manage your blood sugar:

Monitor Regularly: Regularly check your blood glucose levels, especially if you have diabetes or are at risk. Keep a log of your readings.
Follow a Balanced Diet: Focus on whole grains, lean proteins, and plenty of fruits and vegetables. Limit sugary drinks and processed foods.
Exercise Regularly: Aim for at least 30 minutes of moderate-intensity exercise most days of the week.
Manage Stress: Practice stress-reduction techniques such as yoga, meditation, or deep breathing.
Work with Your Healthcare Team: Regularly consult with your doctor, diabetes educator, and registered dietitian to create a personalized management plan.

Common Mistakes to Avoid

Ignoring Fluctuations: Don't dismiss occasional high or low readings. Consistent patterns warrant attention.
Self-Adjusting Medication: Never adjust your medication dosage without consulting your doctor.
Relying Solely on Supplements: While some supplements may help, they should not replace prescribed medication or lifestyle changes.
Using expired testing supplies: This can affect the reading of your meter. Always check the expiration date.

When to Seek Medical Attention

It’s crucial to seek immediate medical attention if you experience any of the following:

Severe Hyperglycemia: Extremely high blood sugar (e.g., above 300 mg/dL or 16.7 mmol/L), especially if accompanied by symptoms like excessive thirst, frequent urination, blurred vision, or confusion.
Severe Hypoglycemia: Extremely low blood sugar (e.g., below 70 mg/dL or 3.9 mmol/L), especially if accompanied by symptoms like shakiness, sweating, dizziness, or loss of consciousness.
Diabetic Ketoacidosis (DKA): A serious complication of diabetes characterized by high blood sugar, ketones in the urine, and symptoms like nausea, vomiting, abdominal pain, and difficulty breathing.

Conclusion

Understanding your blood glucose test results, whether in mg/dL or mmol/L, is paramount for effective diabetes management and overall health. By knowing the conversion between these units, recognizing target blood glucose ranges, and understanding the factors that influence blood sugar levels, you can proactively manage your health and work with your healthcare team to develop the best course of action. Regular monitoring, a balanced lifestyle, and timely medical intervention are key to maintaining healthy blood glucose levels and preventing complications. A1C Vs Fasting Glucose Which Blood Sugar Test Is Better