Getting blood test results back can feel like reading a foreign language. You see a list of numbers, a few abbreviations, and maybe a flag or two. The good news is that some of the most common tests are easier to understand than they look.
This guide walks you through tests that are often used to check blood sugar and blood fats, what the numbers mean, and the typical ranges published by trusted U.S. health agencies. One important note before we start: this article is for learning, not for diagnosing yourself. A licensed clinician looks at your results alongside your health history, symptoms, and other tests to decide what they mean for you.
What a metabolic blood panel can include
The phrase metabolic panel can mean different things depending on who orders it. In this article, we focus on three tests that are often checked together:
- Hemoglobin A1C, which reflects your average blood sugar over a few months
- Fasting blood glucose, which shows your blood sugar at one point in time after not eating
- A lipid panel, which measures cholesterol and triglycerides
Hemoglobin A1C
Hemoglobin is a protein in your red blood cells. When sugar (glucose) is in your blood, some of it sticks to hemoglobin. According to MedlinePlus, the A1C test measures the percentage of your hemoglobin that is coated with glucose.
Red blood cells live about three months. So A1C gives a picture of your average blood sugar over the past two to three months. That makes it different from a single glucose reading, which can change from hour to hour.
The CDC and MedlinePlus publish these ranges for A1C:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or higher
A1C is not a perfect fit for everyone. MedlinePlus notes that conditions affecting red blood cells, such as anemia or other blood disorders, can make A1C less accurate for diagnosing diabetes. Kidney failure, liver disease, pregnancy, and certain medicines, including opioids and some HIV medicines, may also affect results.
Fasting blood glucose
A fasting blood sugar test measures the glucose in your blood after an overnight fast. That means you do not eat overnight before the test. Because food raises blood sugar, fasting helps give a clearer baseline.
The CDC lists these fasting blood sugar ranges:
- Normal: 99 mg/dL or below
- Prediabetes: 100 to 125 mg/dL
- Diabetes: 126 mg/dL or above
The unit mg/dL stands for milligrams per deciliter. It tells you how much glucose is in a set amount of blood.
The lipid panel
A lipid panel, often called a cholesterol test, looks at fats in your blood. MedlinePlus explains that it measures four things.
LDL cholesterol
LDL is often called bad cholesterol. According to the CDC, high levels of LDL can lead to plaque buildup in your arteries. MedlinePlus lists a healthy LDL level for adults age 20 and older as less than 100 mg/dL. Sometimes LDL is measured directly. Other times, it is estimated from your total cholesterol, HDL, and triglycerides.
HDL cholesterol
HDL is often called good cholesterol because it helps get rid of LDL. The CDC notes that high levels of HDL can lower your risk of heart disease. The CDC lists a goal of at least 40 mg/dL for men and at least 50 mg/dL for women. MedlinePlus says 60 mg/dL or higher is best.
Triglycerides
Triglycerides are a type of fat found in your blood. MedlinePlus lists these ranges for adults:
- Healthy: less than 150 mg/dL
- Borderline high: 150 to 199 mg/dL
- High: 200 to 499 mg/dL
- Very high: 500 mg/dL and higher
Total cholesterol
This is a measure of the total amount of cholesterol in your blood. For adults 20 and older, MedlinePlus lists a healthy total cholesterol level as less than 200 mg/dL.
High cholesterol usually does not cause symptoms you can notice. The CDC says the only way to know if you have it is to get your cholesterol checked by your health care team.
You may be asked to fast (not eat or drink) for 9 to 12 hours before a lipid panel. Your provider will tell you if you need to.
Why ranges vary from lab to lab
You may notice that the normal range printed on your report does not match a number you read online. That is expected. MedlinePlus explains that labs often use different testing methods, so they often use different reference ranges. That is also why you can't directly compare test results from different labs.
The best guide is the reference range listed on your own lab report, read together with your clinician.
Other things can affect your results too. MedlinePlus lists:
- Eating or drinking certain foods and drinks
- Taking certain medicines or supplements
- Exercising hard before your test
- Having a menstrual period at the time of your test
- Not following prep steps, such as fasting
Following your provider's instructions carefully helps make your results as accurate as possible.
How often cholesterol is checked
MedlinePlus notes that adults ages 20 to 65 are generally tested every 5 years. Men ages 45 to 65 and women ages 55 to 65 may be tested every 1 to 2 years. Adults over 65 should be tested every year. Your clinician may suggest a different schedule based on your health.
Questions to ask your clinician
- Which of my results are outside the lab's reference range, and what might that mean for me?
- Do I need to repeat any tests, and should I fast first?
- Could my medicines, supplements, or health conditions be affecting my numbers?
- How do these results fit with my family history and other risk factors?
- When should I be tested again?
The bottom line
A1C, fasting glucose, and a lipid panel give a useful snapshot of your blood sugar and blood fats. The ranges above are a helpful starting point. Still, your lab's own reference range and your full health picture matter most, and a licensed clinician is the right person to interpret your results.
At-home testing is coming to Talvi, with results explained by a licensed provider. And at Talvi, a licensed clinician reviews your health history before anything is prescribed.