A1c shows average blood sugar over 2 to 3 months, a lipid panel measures cholesterol and triglycerides, liver enzymes flag liver stress such as fatty liver, and eGFR estimates kidney filtering. Here is what each test means and the reference points public health sources use.
A basic metabolic workup usually answers four questions: how your body is handling blood sugar (A1c and fasting glucose), how much cholesterol and fat are circulating in your blood (the lipid panel), whether your liver is under stress (liver enzymes), and how well your kidneys are filtering (eGFR and urine albumin). Each result is a snapshot, and the most useful information often comes from comparing results over time. This guide explains what each test measures and the reference points that the CDC, NIH and MedlinePlus use, so you can have a more informed conversation with your licensed provider.
| Test | What it measures | Reference points from public health sources |
|---|---|---|
| A1c | Average blood sugar over the past 2 to 3 months | Normal below 5.7%; prediabetes 5.7 to 6.4%; diabetes 6.5% or above (CDC) |
| Fasting glucose | Blood sugar after an overnight fast | Normal 99 mg/dL or below; prediabetes 100 to 125; diabetes 126 or above (CDC) |
| Lipid panel | Total, LDL and HDL cholesterol, triglycerides | Adults: total under 200 mg/dL, LDL under 100, non-HDL under 130 (MedlinePlus) |
| Liver panel | ALT, AST, ALP, GGT, bilirubin, albumin and others | Interpreted as a pattern by your clinician (MedlinePlus) |
| eGFR | How well the kidneys filter blood | 60 or more is in the normal range (NIDDK) |
| Urine albumin (UACR) | Protein leaking into urine | 30 mg/g or less is normal (NIDDK) |
| TSH | Signal from the pituitary to the thyroid | Too high or too low may point to a thyroid problem (MedlinePlus) |
Labs may use slightly different reference ranges, and your provider interprets results in the context of your age, history and other tests.
The CDC explains that the A1c test reflects your average blood sugar over the past 2 or 3 months. A fasting blood sugar test measures glucose after an overnight fast. The CDC thresholds are:
The CDC emphasizes that prediabetes and type 2 diabetes often have no symptoms, which is why testing matters for people with risk factors, and that catching prediabetes early can help prevent or delay type 2 diabetes. The CDC also notes that if your blood sugar was checked at a health fair or pharmacy, your clinician may want to re-test you to make sure the result is accurate.
A lipid panel measures LDL cholesterol, HDL cholesterol, total cholesterol and triglycerides. MedlinePlus explains that too much LDL raises the risk of plaque buildup in the arteries, while HDL helps clear LDL. It lists these healthy levels for adults 20 and older:
| Measure | Men 20 and older | Women 20 and older |
|---|---|---|
| Total cholesterol | Under 200 mg/dL | Under 200 mg/dL |
| Non-HDL cholesterol | Under 130 mg/dL | Under 130 mg/dL |
| LDL cholesterol | Under 100 mg/dL | Under 100 mg/dL |
| HDL cholesterol | 60 mg/dL or higher is best; under 40 is low | 60 mg/dL or higher is best; under 50 is low |
Your report may say the LDL is "calculated," which MedlinePlus notes means it is estimated from your total cholesterol, HDL and triglycerides.
Triglycerides are a type of fat your body stores from extra calories. According to MedlinePlus, high levels are very common and can be linked to eating patterns high in sugar and refined carbohydrates, low activity, excess weight, poorly controlled diabetes, thyroid, kidney or liver disease, heavy alcohol use, inherited conditions and some medicines. Extremely high triglycerides also raise the risk of acute pancreatitis. You may be asked to fast for 9 to 12 hours before a lipid test, so check the instructions.
A liver panel, often included in a comprehensive metabolic panel, measures substances such as ALT, AST, ALP and GGT (enzymes mainly made in the liver), bilirubin and albumin. MedlinePlus cautions that liver function tests alone usually cannot diagnose a specific disease. Instead, clinicians look at the pattern of results and may order more tests if something is abnormal.
One of the most common reasons for liver stress in people with excess weight is fatty liver. The NIDDK explains that nonalcoholic fatty liver disease (NAFLD) is now also called metabolic dysfunction-associated steatotic liver disease, or MASLD. Its more serious form, with inflammation and liver damage, is called MASH. NIDDK estimates that about 24 percent of US adults have NAFLD, and research suggests it is present in up to 75 percent of people with overweight and more than 90 percent of people with severe obesity, as well as one-third to two-thirds of people with type 2 diabetes.
People with fatty liver also have a higher risk of heart disease, which NIDDK identifies as the most common cause of death in people with NAFLD. That is a good reason to look at liver results together with your lipid and blood sugar results rather than in isolation.
The NIDDK explains that providers check kidney health with two tests. The first is a blood test that estimates glomerular filtration rate (GFR):
The estimate is based on creatinine, a waste product from normal muscle breakdown. The second test, the urine albumin-to-creatinine ratio (UACR), looks for protein leaking into the urine; NIDDK lists 30 mg/g or less as normal. Early kidney disease usually has no symptoms, and the NIDDK recommends yearly testing for people with diabetes. Our hydration guide covers fluids during weight treatment.
A TSH test is often added when symptoms such as fatigue or weight change raise the question of thyroid function. MedlinePlus explains that a TSH level that is too high or too low may be a sign of a thyroid problem. Our article on thyroid health and weight covers this in more detail.
Single values bounce around. A few habits make your labs more useful:
It depends on the test. MedlinePlus notes that you may need to fast for 9 to 12 hours before a cholesterol or triglycerides test and for about 10 to 12 hours before liver function tests, and a fasting glucose test is done after an overnight fast. Your provider or lab will tell you what applies.
The CDC defines prediabetes as an A1c of 5.7 to 6.4 percent. Below 5.7 percent is considered normal, and 6.5 percent or above is in the diabetes range. Your clinician may repeat a test to confirm a result before making a diagnosis.
Trials of weight-management medications have reported improvements in blood sugar, lipids and other cardiometabolic markers on average. In SURMOUNT-1, all prespecified cardiometabolic measures improved with tirzepatide. Individual changes vary, and your provider can tell you which markers to watch in your case.
Creatinine comes from normal muscle breakdown, and providers use it to estimate eGFR. The NIDDK considers an eGFR of 60 or more to be in the normal range and less than 60 a possible sign of kidney disease. Because many factors can affect a single result, your clinician will interpret it alongside your history and may repeat the test.
Lab results are most meaningful when someone who knows your history reviews them with you. Bring copies of past results if you have them, list your medications and supplements, and ask which numbers your licensed provider wants to track during any treatment. This article is educational and does not determine eligibility for any treatment.
Written by the NewDay Wellness editorial team from the sources above and checked against them before publication, and medically reviewed by Dr. Sean Arora and Dr. Shannon Arora of Arora Health & Aesthetics; see our editorial standards. This article is educational and does not diagnose conditions, establish eligibility for any medication, or replace care from a licensed provider. Compounded medications are not FDA-approved.
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