How to Read Diabetes Lab Results: A1C, Glucose, Lipids, Kidney Tests, and Questions to Ask

Quick answer: A diabetes lab visit usually bundles a handful of tests that answer different questions: how high your glucose runs (A1C, fasting glucose, sometimes a glucose tolerance test), how your blood fats look (lipid panel), how your kidneys are filtering and leaking (eGFR and a urine albumin-to-creatinine ratio, or UACR), and sometimes how your liver and vitamin B12 are doing. Reported guidance gives targets for many of these, but “normal” ranges differ between labs, and your own goals depend on your health. Look at the units, the lab’s own reference range, the date, and the trend. Do not diagnose or change treatment from a single number. Bring your results to your clinician and ask what each means for you.

Before the numbers: three habits that make results easier to read

Lab reports are dense, and the most common mistakes come from reading a number without its context. Start with three habits. First, check the units. Glucose can appear in mg/dL or mmol/L, A1C can appear as a percentage or in mmol/mol, and cholesterol may be in mg/dL or mmol/L. Second, find the lab’s own reference range, which prints beside each value and is not identical from one lab to the next. A University of Washington lab-medicine test guide, for example, prints a total cholesterol reference of below 210 mg/dL, while the American Diabetes Association (ADA) frames its lipid goals around risk, not a single “normal.” Both can be right for their purpose. Third, look at the trend. A result that is slightly outside a range once, then back inside it, says something different from a number that climbs over three visits.

This guide covers the tests most people with type 2 diabetes meet. It is general education, I am not a physician, and nothing here diagnoses a condition or changes a treatment. I draw on pages I could actually read: ADA Standards of Care summaries and infographics, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), the National Kidney Foundation (NKF), a University of Washington lab test guide, and news summaries. The ADA’s full Standards, PubMed, and the CDC site were not reachable from my tools, so I name each source and flag what I could not confirm.

Glucose tests: what they measure and the numbers that define diabetes

Four tests describe your blood sugar from different angles. A1C reflects the sugar attached to hemoglobin and is a rough average of the past two to three months. A fasting plasma glucose is a single reading, usually after an overnight fast. An oral glucose tolerance test (OGTT) measures glucose two hours after a sugary drink. A random glucose can be drawn at any time. The cutoffs below come from a Johns Hopkins diabetes guide table, which cites the ADA, and from the National Kidney Foundation’s lab-values page.

Test	Prediabetes range	Diabetes range
A1C	5.7 to 6.4%	6.5% or higher (the Johns Hopkins table prints “>6.5”, which looks like a typo; the NKF page says 6.5% or higher)
Fasting plasma glucose	100 to 125 mg/dL	126 mg/dL or higher
2-hour glucose after a 75 g OGTT	140 to 199 mg/dL	200 mg/dL or higher
Random glucose	No range listed in the sources I read	200 mg/dL or more at any time “may indicate diabetes” (NKF)

Sources: Johns Hopkins Diabetes Guide table of prediabetes and diabetes categories; NKF page on lab values. I did not find a confirmation rule (such as repeating a test) on the pages I could read, so ask your clinician how a diagnosis is confirmed. A NIDDK page says point-of-care A1C devices should not be used for diagnosis.

These are diagnostic thresholds, not treatment goals. Once someone has diabetes, the goals are different, which the next table covers. For the differences between the diagnostic tests, see A1C vs fasting glucose vs the glucose tolerance test, and for the meaning of the prediabetes range read what does an A1C of 5.7 mean.

Glucose targets once you have diabetes

The ADA’s targets for many non-pregnant adults, as quoted in a November 2023 US Pharmacist article and a Diatribe summary of the 2023 Standards, are an A1C below 7%, a before-meal capillary glucose of 80 to 130 mg/dL, and a peak after-meal glucose below 180 mg/dL measured one to two hours after the start of the meal. For continuous glucose monitor (CGM) users, the same sources list time in range, 70 to 180 mg/dL, above 70% of the day, time below 70 mg/dL under 4%, and time below 54 mg/dL under 1%. A 2026 summary of the Standards, from 2 Minute Medicine, repeats the A1C below 7% and time in range above 70% goals. These numbers are general and are individualized. Our companion guide, A1C goals by age with type 2 diabetes, explains why a looser goal such as below 8% can be right for some people.

The same A1C in everyday glucose units

An A1C result can be translated into an estimated average glucose (eAG) with the formula from the A1C-Derived Average Glucose study: eAG in mg/dL equals 28.7 times A1C minus 46.7. I computed these three common points myself, and our A1C and average glucose calculator does it for any value.

A1C 6.5% gives about 140 mg/dL.
A1C 7.0% gives about 154 mg/dL.
A1C 8.0% gives about 183 mg/dL.

A secondary summary of the study describes individual variation of about ±15 mg/dL, so treat these as estimates. A NIDDK page also notes that some anemias, sickle cell disease and hemoglobin C disease, significant kidney disease, liver failure, and some hemoglobin variants can make A1C unreliable. If your A1C does not match your meter or CGM averages, raise it with your clinician. The CGM vs A1C guide explains what each tells you.

The lipid panel: four numbers and a lot of confusion

A standard lipid panel reports total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides. Many labs also report non-HDL cholesterol, which is total cholesterol minus HDL. The University of Washington lab-medicine guide lists all five components and prints reference ranges tied to the 2019 American College of Cardiology and American Heart Association primary prevention guideline. The ADA’s own lipid goals for adults with diabetes, shown in a 2025 ADA infographic, are framed around risk. Both are in the table.

Measure	Lab reference or interpretation (University of Washington guide)	ADA goal for adults with diabetes (2025 infographic)
Total cholesterol	Reference below 210 mg/dL; 210 to 239 is hypercholesterolemia; 240 or higher is significant	Not given in the source I read
LDL cholesterol	Reference below 160 mg/dL; 160 to 189 hypercholesterolemia; 190 or higher severe. A common treatment target in many patients is 70 mg/dL	Below 70 mg/dL for primary prevention; below 55 mg/dL for secondary prevention (people with existing cardiovascular disease)
HDL cholesterol	Reference: 40 or higher for men, 50 or higher for women. Low HDL is linked to metabolic syndrome	A 2023 Diatribe summary of the ADA targets lists at least 40 for men and 50 for women
Triglycerides	Reference below 175 mg/dL; 175 or higher is hypertriglyceridemia (the page links levels above 150 to metabolic syndrome)	Moderate elevation is fasting above 150 or non-fasting above 175; target below 150 in people with or at high risk of cardiovascular disease; fasting 500 or higher should be evaluated for secondary causes
Non-HDL cholesterol	Reference below 190 mg/dL; 190 to 219 hypercholesterolemia; 220 or higher severe. A common target in many patients is 100 mg/dL	Not addressed in the ADA infographic I read

The ADA infographic also says treatment is reasonable at ages 20 to 39 with diabetes and other risk factors, to target at ages 40 to 75, and that continuing a statin over 75 is reasonable. Lipid panels are suggested at diagnosis and annually, and 4 to 12 weeks after starting or adjusting lipid-lowering drugs. Reference ranges vary by lab, and the numbers above are not medical advice.

Why do the University of Washington reference numbers look looser than the ADA goals? The lab’s ranges describe what is typical or what flags a result for review in a general population, and the ADA’s goals describe where treatment aims in people with diabetes who have added cardiovascular risk. When your report prints a flag, that is the lab’s range. When your clinician says “your LDL goal is under 70,” that is risk-based. Ask which one you are looking at.

Worked example: two quick calculations from a lipid panel

Take a made-up panel: total cholesterol 185, LDL 92, HDL 44, triglycerides 168, all in mg/dL. Non-HDL cholesterol is total minus HDL, so 185 − 44 = 141 mg/dL. The triglyceride-to-HDL ratio is 168 ÷ 44 = 3.8. Our triglyceride-to-HDL calculator and complete cholesterol numbers calculator run these for your own values. These are screening arithmetic, not a diagnosis. Whether the made-up numbers are “good” depends on the person’s overall risk, and the ADA ties LDL goals to risk, so the panel only makes sense in context.

Kidney tests: eGFR and UACR

Diabetes can damage the kidneys slowly, often without symptoms, which is why two tests are routine. The eGFR (estimated glomerular filtration rate) is a blood-based estimate of how well the kidneys filter, calculated from creatinine and other factors. The UACR (urine albumin-to-creatinine ratio) measures albumin leaking into urine, relative to creatinine. A NIDDK quick-reference sheet says albuminuria is present when UACR is greater than 30 mg/g, and says to assess urine albumin yearly in people with type 2 diabetes and in people with type 1 diabetes for five years or more. It also says NIDDK recommends reporting eGFR values of 60 or above as “>60” because exact values above 60 are not reliable. The NKF heat map card gives the categories in the table.

eGFR category	eGFR (mL/min/1.73 m²)
G1	90 or higher
G2	60 to 89
G3a	45 to 59
G3b	30 to 44
G4	15 to 29
G5	Below 15 (the NKF page calls below 15 a marker of kidney failure)

Source: NKF CKD heat map card. An NKF page says an eGFR below 60 is a sign the kidneys may not be working properly.

UACR category	UACR (mg/g)	NKF label
A1	Below 30	Normal to mildly increased
A2	30 to 300	Moderately increased
A3	Above 300	Severely increased

Source: NKF CKD heat map card (which lists the numbers without units) and the NIDDK UACR quick reference sheet (which gives mg/g and says albuminuria is present when UACR is greater than 30 mg/g). On the real heat map, the two categories are read together in a grid of risk colors. A single high UACR may not mean kidney disease, so a clinician decides what repeat testing is needed. I did not find a repeat-testing rule on the pages I read.

The ADA’s 2026 Standards, as paraphrased by 2 Minute Medicine, discuss medicine choices for people with kidney disease, including that certain drug classes are recommended in some situations, and they set a blood pressure goal of below 130/80. That is medication territory for the prescriber, so this guide does not go further. If you have reduced eGFR or albuminuria, your food guidance may change too, for example for protein, potassium, or sodium. Ask your clinician or a dietitian before changing what you eat.

Vitamin B12 if you take metformin

Long-term metformin use is associated with lower vitamin B12. A DiabetesEd.net page summarizing the ADA Standards, published in March 2022 and not naming the edition, says the Standards advise considering B12 measurement for people with peripheral neuropathy or unexplained anemia, and notes the link with long-term metformin, but the page says there was no clear recommendation to check B12 routinely in everyone on metformin. Because that is a secondhand summary of one edition, ask your clinician how often your B12 should be checked. For more, read our posts on metformin and B12 deficiency and how often to check B12 on metformin. No dose of any supplement is recommended here.

Liver tests: ALT, AST, and the FIB-4 score

Fatty liver disease is common in type 2 diabetes. A 2023 ADA update, reported by MDedge on June 27, 2023, recommends screening adults with type 2 diabetes and prediabetes with the FIB-4 index, a calculation from age, liver enzymes (AST and ALT), and platelet count. The report says a FIB-4 of 1.3 or higher suggests high risk for significant fibrosis and above 2.6 suggests very high risk. A Duke Health page on the same update says FIB-4 is seen as better than checking liver enzymes alone, and that people at higher risk get a more definitive test such as liver elastography. Neither source gave a repeat interval.

The commonly published FIB-4 formula is age times AST, divided by platelet count (in 10⁹/L) times the square root of ALT. I did not re-verify the formula on a page I read, so treat it as the standard published form and ask your lab or clinician for your actual score. Worked example with made-up numbers: age 58, AST 34, ALT 41, platelets 210. FIB-4 = 58 × 34 ÷ (210 × √41) = 1.47. In the reported cutoffs, that value is above 1.3 and below 2.6, an in-between result a clinician would interpret with the rest of the picture. Our fatty liver (MASLD) guide covers what the diagnosis means.

Insulin-related numbers: HOMA-IR, TyG, and triglyceride-to-HDL

You may see three research-style estimates of insulin resistance on health sites. HOMA-IR uses fasting glucose and fasting insulin. The triglyceride-glucose (TyG) index uses fasting triglycerides and fasting glucose. The triglyceride-to-HDL ratio uses two lipid numbers. None of them is a routine part of a standard diabetes visit, and I did not find an official cutoff for any of them on a page I could read, so I do not give one. Ask your clinician whether any of them would change what you do.

For arithmetic only: with a made-up fasting glucose of 104 mg/dL and fasting insulin of 11 µU/mL, HOMA-IR (glucose × insulin ÷ 405) is 2.82. With the same glucose and triglycerides of 168 mg/dL, the TyG index (the natural log of triglycerides × glucose ÷ 2) is 9.08. Our HOMA-IR calculator, TyG index calculator, and triglyceride-to-HDL calculator do the math for you, and you can read about each in our explainers on HOMA-IR, the TyG index, and the triglyceride-to-HDL ratio. The two formulas are the commonly published forms and I did not re-verify them here.

Reading a report line by line

Most lab portals show each result with a value, units, a reference range, and a flag such as H for high or L for low. Treat the flag as a prompt to look, not as a verdict. A flag compares your number to the lab’s reference range, which is built from a general population, so a flagged number might be perfectly fine for you and an unflagged number might be above your own goal. A result that matters most to your treatment might not be flagged at all. The A1C goal for someone with diabetes, for example, is below 7% in the general ADA target, but a lab report may not flag a 6.8%.

Next, check the date and the collection conditions. A fasting glucose collected after breakfast will run higher than one collected after an overnight fast. A urine test collected during a urinary infection or after intense exercise can read differently. I did not find a source I could read that lists all the causes of a temporary rise in urine albumin, so do not guess. If a result surprises you, ask whether it should be repeated, and whether anything about the day of the test could have affected it.

Finally, group results by the question they answer. Glucose results answer “how high does my sugar run?” Lipids answer “what is my cholesterol-related risk?” Kidney tests answer “are my kidneys filtering and leaking normally?” Liver tests answer “is there a sign of fat or scarring?” Putting results in these four buckets makes a long portal page much easier to read, and it makes your questions for the clinician shorter and sharper.

Why numbers move between visits

Everyone’s results change. A1C moves with the past two to three months of glucose, so a better stretch of eating, walking, sleep, or medicine adherence shows up slowly and a bad month takes a while to appear. Glucose on a single day moves with food, activity, stress, illness, and sleep. Lipids can shift with weight, food, alcohol, and medicines. Kidney numbers can shift with hydration and illness, which is another reason a clinician looks at trends. Lab methods differ, so a change of lab can look like a change in you. A small change between two reports is usually noise, and a steady direction across several is the signal worth discussing. Keeping a simple log of your own results with dates, which you can do in a notes app, makes that trend easy to see and to share.

How often these tests are usually done

Test	Reported frequency	Source
A1C	At least twice a year when meeting goals with stable control; quarterly when therapy has changed or goals are not met	NGSP page on the ADA clinical use guidance; US Pharmacist summary of the 2023 Standards
Lipid panel	At diagnosis and annually; 4 to 12 weeks after starting or adjusting lipid-lowering drugs	2025 ADA lipid infographic
Urine albumin (UACR)	Yearly in type 2 diabetes	NIDDK UACR quick reference sheet
Liver (FIB-4)	Screening recommended; interval not stated in the sources I read	MDedge and Duke Health reports of the 2023 ADA update
Vitamin B12	Consider with neuropathy or unexplained anemia; no routine rule in the summary I read	DiabetesEd.net summary (2022)

Frequencies change with your health and with new editions of the Standards. Ask your clinician for your own schedule.

Getting ready for a lab visit

Ask about fasting. Some tests, such as a fasting plasma glucose, require it. The ADA lipid infographic gives a non-fasting triglyceride threshold, which suggests non-fasting lipid draws are acceptable in some cases. Ask which applies to your tests.
Take your medicines as directed unless told otherwise, and tell the lab and your clinician what you take, including supplements.
Bring your last results. Trends are more useful than single values.
Write down symptoms and low blood sugar episodes since the last visit.
Ask for the report with reference ranges and units, and for the lab’s name, since methods vary.

What to do in each situation

If you have prediabetes

Your results sit in the ranges in the first table. The questions are how often to retest and what to change. Read the complete A1C and glucose guide and the diabetes food guide.

If you have type 2 diabetes and take no glucose-lowering medicine

Use the general targets as a starting point for your conversation, and keep your annual kidney, lipid, and other checks on the calendar. Home data from a meter or CGM can add context. See how to read your CGM data and the post-meal glucose tracker.

If you are an older adult

Targets depend on health and function more than on age, and the ADA’s older-adult table describes looser goals for some people. Read A1C goals by age.

If you take medicines for glucose, cholesterol, or blood pressure

Lab results often guide those medicines, and the schedule of tests can be tied to starting or adjusting them. Do not change a dose or stop a medicine because of a number you read here. Contact your prescriber, and call your care team promptly if you have symptoms of low blood sugar.

Common mistakes

Reading a number without units or the lab’s range.
Treating a diagnostic cutoff as a treatment goal. 6.5% defines diabetes in the diagnostic tables. It is not the goal for someone already diagnosed.
Comparing LDL goals from different sources without asking which applies. A lab range and an ADA risk-based goal answer different questions.
Skipping the kidney test because you feel fine. Kidney damage can be silent, and yearly UACR is the reported schedule.
Self-adjusting medicine from one result.
Believing a single odd value. Repeat or trend it with your clinician.

Myth versus fact

Common belief	What the sources say
“Normal on the lab report means I have no problem.”	Lab reference ranges describe typical values, and the ADA’s goals for people with diabetes are risk-based and can be stricter.
“A1C is the only number that matters.”	Lipids, kidney tests, and liver screening are separate parts of the picture, with their own schedules.
“If my A1C is fine, my kidneys are fine.”	Kidney damage is checked with eGFR and UACR, not A1C. UACR is reported yearly in type 2 diabetes.
“Fasting is required for every test.”	Some tests require it, and some, like triglycerides, can be non-fasting. Ask the lab.
“Metformin means a B12 test every visit.”	The summary I read found no routine rule for everyone on metformin, and suggested considering it with neuropathy or unexplained anemia. Ask your clinician.

Twelve questions to bring to your clinician

Which of my results are outside the lab’s range, and which are outside my own goal?
What is my A1C goal and why?
What is my LDL goal given my overall risk?
When were my kidney tests last done, and what were my eGFR and UACR?
If my UACR was high, when do we repeat it?
Do I need a liver screening, and how is my FIB-4 or other score?
Should my vitamin B12 be checked, given my medicines?
Could anything make my A1C unreliable, such as anemia or a hemoglobin variant?
Do I need to fast for my next draw?
Which tests will you order next, and how often?
Are any of my medicines tied to these results, and what monitoring do they need?
What should I do at home between visits?

Frequently asked questions

What is a normal A1C?

A1C below 5.7% is the usual non-diabetic range, 5.7 to 6.4% is the prediabetes range, and 6.5% or higher is in the diabetes range in the tables I read. For people who already have diabetes, goals differ.

What is a good fasting glucose with diabetes?

Reported ADA targets for many non-pregnant adults are 80 to 130 mg/dL before meals. Your own target depends on your health and medicines.

What does an eGFR of 60 mean?

NKF describes an eGFR below 60 as a sign the kidneys may not be working properly. NIDDK recommends reporting values of 60 or above as “>60.” Ask your clinician what your result means for you.

What is a UACR and why does it matter?

It is a urine test that compares albumin to creatinine. Above 30 mg/g indicates albuminuria, a marker of kidney damage per NIDDK, and yearly testing is reported for type 2 diabetes.

What LDL should I aim for with diabetes?

A 2025 ADA infographic lists below 70 mg/dL for primary prevention and below 55 mg/dL for secondary prevention. Lab reference ranges can differ.

Do I need to fast for cholesterol testing?

Some tests need fasting and some do not. The ADA infographic gives a non-fasting triglyceride threshold. Ask your lab or clinician.

How often should I get my A1C checked?

At least twice a year when meeting goals with stable control, and quarterly when therapy has changed or goals are not met, per the sources quoted above.

Why do two labs give different results?

Methods and reference ranges vary, and some A1C methods are affected by hemoglobin variants. NGSP lists affected methods.

What is FIB-4?

A calculation from age, AST, ALT, and platelets used to screen for liver scarring risk in type 2 diabetes. Reported cutoffs are 1.3 and 2.6. Ask your clinician about your score.

Can this guide tell me what my results mean?

No. It explains what the numbers measure and what published guidance reports. Your clinician interprets your results.

Sources

The ADA Standards of Care, PubMed, and the CDC were not reachable from the tools used to prepare this page. Ranges vary by lab. Confirm everything with your care team.

About the author: Charles Kirkland is the founder of Metabolic Clarity Labs and author of The Journey Back. He is not a physician. This is general education, not a medically reviewed treatment plan.

Sources checked October 31, 2026. Discuss personal decisions with a qualified clinician. Do not start, stop, or change prescribed treatment based on this article.