Blood Sugar 142 mg/dl — Too High? Fasting & After Eating
Where 142 mg/dl sits — adjust to your situation
142 mg/dl as a fasting reading
Diabetes range
A fasting reading of 126 mg/dl or higher falls into the diabetes range. Diagnosis requires a repeat test on another day — take this result to your doctor.
Fasting = no food for at least 8 hours, typically first thing in the morning. More on fasting readings.
142 mg/dl after eating
Prediabetes range
Between 140 and 199 mg/dl two hours after a meal suggests impaired glucose tolerance, the post-meal form of prediabetes.
Guidelines measure 2 hours after the start of a meal. More on post-meal readings.
A fasting 142 without a diagnosis: the confirmation path
A fasting value of 142 is 16 points over the 126 line that defines the diabetes range. If you have never been told you have diabetes, this reading is a reason to book an appointment in the coming days or weeks. It is not an emergency, and on its own it is not a diagnosis either. Diabetes is diagnosed on lab tests, and in someone without obvious symptoms it takes two abnormal results.
Those two results can come from the same blood draw (for example, a fasting glucose of 126 or more plus an A1C of 6.5 % or more) or from the same test repeated on a different day. A random glucose of 200 or more with classic symptoms such as heavy thirst and frequent urination is the only situation where one result is enough.
Tests your doctor is likely to order
- Fasting plasma glucose from a vein, after at least eight hours without calories. Lab analyzers are more precise than a fingertip meter.
- A1C, which reflects the average of the past two to three months and needs no fasting. Many doctors order it in the same draw.
- A 75 g oral glucose tolerance test in some cases, especially when the first results disagree or the doctor wants the most sensitive test.
If diabetes is confirmed, a wider baseline usually follows: kidney function and urine albumin, cholesterol, blood pressure, a foot check and an eye exam referral. Those are not part of the diagnosis, but they set a starting point for later comparison.
When the lab and the meter tell different stories
A home meter is allowed to be off by up to 15 % at this level, so a displayed 142 corresponds to a true value of roughly 121 to 163. That window dips under 126. It is quite possible for a lab fasting glucose to come back at 118 or 124 after a home reading of 142, especially if the strips were old, the fingers were not washed, or the “fasting” check followed a late snack.
Discordant results are handled in a standard way: the test that came back over its threshold is repeated. If it is abnormal again, that confirms diabetes. If it is normal, the result is usually recorded as prediabetes or normal, and testing is repeated later on the schedule your doctor sets. Either way, do not throw away your home log. A week of morning values written down with times is useful context at the appointment.
Which type? Questions that may come up
Most adults with a fasting value in this range turn out to have type 2 diabetes or prediabetes. A doctor will still ask a few questions that help rule out other types: Has there been unintended weight loss? Are you very thirsty, getting up at night to urinate, or feeling unusually tired? Is there a personal or family history of autoimmune conditions? Were you diagnosed with gestational diabetes in a past pregnancy? Are you taking steroids or other medicines that raise glucose? In younger or lean adults, or when glucose is rising fast, antibody tests for type 1 diabetes may be added. The fasting blood sugar page explains how to prepare a clean fasting test.
Measured right after exercise?
There is no official range for readings taken during or just after a workout, so the two classifications above do not apply to them. How exercise moves blood sugar.
How 142 mg/dl compares to a typical day
Typical day without diabetes; your reading is the horizontal line — higher than a typical day reaches two hours after a meal; brief one-hour peaks this high are common.
What to do with a reading of 142 mg/dl
Book a doctor's appointment to confirm with a lab test (fasting glucose or A1C). If you are already diagnosed, this reading belongs in your log for your care team.
What actually moves the number: How to lower blood sugar, Foods that steady your glucose and Exercise and blood sugar.
Save this reading
Stored only in your browser on this device. See the privacy policy for what analytics records when you allow it. Build a history you can chart, print for your doctor, or export.
Questions about 142 mg/dl
Is 142 mg/dl blood sugar normal?
It depends on when you measured. Fasting, 142 mg/dl is diabetes range (normal fasting range: 70–99 mg/dl). Two hours after a meal it is prediabetes range (normal post-meal range: 70–139 mg/dl).
What is 142 mg/dl in mmol/L?
142 mg/dl equals 7.9 mmol/L. Divide mg/dl by 18 to convert (used in the UK, Canada, Australia and most of Europe).
Does one reading of 142 mg/dl mean I have diabetes?
No single home reading is a diagnosis. Guidelines require a second abnormal lab result, either a different test from the same blood draw or a repeat on another day (fasting glucose, an oral tolerance test, or A1C). But a reading like this is exactly the reason those tests exist — take it to your doctor.
How accurate is a home reading of 142 mg/dl?
Home meters are allowed an error of ±15 mg/dl below 100 mg/dl and ±15 % from 100 up (ISO 15197), so a displayed 142 can correspond to a true value anywhere from 121 to 163 mg/dl. Fasting, that window crosses the 126 mg/dl line — a single home reading of 142 cannot settle which side you are truly on. That is a lab-test question, not a meter question. After a meal, the window touches the 140 mg/dl boundary.
What A1C would 142 mg/dl correspond to?
If 142 mg/dl were your average glucose over three months, it would work out to an A1C of about 6.6 % — at or above the 6.5 % diabetes threshold. A single reading is not an average — but the conversion shows what this level would mean as a habit. How the two measures relate: A1C and blood sugar.
Should I change my diet before the lab test so the result looks better?
No. Eat as you normally do in the days before, and keep only the overnight fast. Cutting carbohydrate sharply for a few days can shift the result and make it less useful. The point of the test is to see your usual state, so that any advice fits your real life.
Can a fasting 142 go back to normal?
Sometimes the lab value is simply lower than the meter reading. And when type 2 diabetes or prediabetes is confirmed early, weight loss, activity and, where needed, medicine can bring fasting values back down. Early confirmation is what makes that easier.
BloodSugarEasy — blood sugar reading report
Reading: 142 mg/dl (7.9 mmol/L)
Fasting classification: Diabetes range · After-meal classification: Prediabetes range
Reference: ADA criteria, reviewed 2026-11-03 · https://bloodsugareasy.com/blood-sugar-142/
Printed: