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Blood Test Tracker

Glucose (2-Hour Postprandial)

Your blood glucose about 2 hours after you start a normal meal. It shows how well your body handles the sugar and starch from food.

AI-verified against cited sources. Awaiting expert reviewAlso called PPBS, PPG, PP2BSLOINC 1521-4

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What it is

A 2-hour postprandial glucose test measures the sugar in your blood about two hours after you start a regular meal. You eat your usual food, not a measured sugar drink. Glucose rises after you eat, and the hormone insulin helps move it into your cells. In people with diabetes the peak usually comes 1 to 2 hours after the meal begins. The test is often written PPBS or PP on reports. It is not the same as the 2-hour value on a glucose tolerance test.

Why it matters

Glucose that stays high after meals is one of the changes seen in prediabetes and diabetes, and it can sometimes be high even when a fasting glucose is in range. Clinicians may use after-meal numbers to see how meals, activity and medicines work together. For a person without diabetes, one result is a snapshot. It depends on what and how much you ate, so it is usually read with a fasting glucose or A1c and sometimes repeated.

If it’s low

A low result two hours after a meal is uncommon in people without diabetes. A sample that sat too long before testing can read falsely low. In people with diabetes, the ADA calls glucose below 70 mg/dL (3.9 mmol/L) low, and below 54 mg/dL (3.0 mmol/L) the more serious level. Low glucose can cause shakiness, sweating and confusion.

Common causes

  • A sample that sat for hours before the blood cells were separated
  • A small or skipped meal, or a long gap since you last ate
  • In people with diabetes, medicines such as insulin or sulfonylureas, which are a frequent cause of low glucose
  • Heavy alcohol use or intense exercise
  • Liver or kidney disease
  • Underactive adrenal glands or certain pituitary conditions
  • Rarely, a drop in glucose a few hours after eating (sometimes called reactive hypoglycemia), or a pancreas tumor that makes too much insulin

What can help

  • If you have diabetes, ask your care team how to prevent and treat low glucose
  • If low glucose happens when you do not have diabetes, ask your clinician whether more testing is needed to find the cause
  • Ask whether the timing of your meals, alcohol or exercise could be involved

If it’s high

A result above your lab's range, often around 140 mg/dL (7.8 mmol/L), means your glucose was still high two hours after the meal started. A big or sugary meal can do this. So can illness, stress or some medicines. Repeated high after-meal results are more common in people with prediabetes and diabetes. This test alone isn't how diabetes is diagnosed, and your clinician can put the number in context.

Common causes

  • A large meal, one high in refined carbohydrates, or a sweet drink with the meal
  • A sample drawn earlier than 2 hours after the meal started, when glucose is often still near its peak
  • Illness, infection, surgery, injury or other stress on the body
  • Some medicines, such as corticosteroids
  • Prediabetes or diabetes
  • Pregnancy, including gestational diabetes
  • Hormone conditions, such as an overactive thyroid or Cushing's syndrome

What can help

  • Ask your clinician whether to repeat the test, or to add a fasting glucose or an A1c
  • Ask whether what you ate, or when the sample was drawn, could explain the result
  • Regular physical activity, a balanced eating pattern and a healthy weight are the main lifestyle levers clinicians discuss for glucose that runs high
  • If you have diabetes, ask your care team how your after-meal numbers fit your plan

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: 70–140 mg/dL. Source: Mayo Clinic Laboratories (read through the testcatalog.org mirror), Journal of Clinical Endocrinology & Metabolism, American Diabetes Association (Diabetes Care). Labs treat below 55 mg/dL or above 450 mg/dL as urgent.

Wellness targets

Narrower ranges some clinicians aim for. Being outside one doesn’t mean something is wrong.

up to 179 mg/dL (diabetes). Evidence: Expert opinion. The ADA lists a peak after-meal glucose below 180 mg/dL (10.0 mmol/L) as a goal for many nonpregnant adults with diabetes, and the IDF notes the same figure as a rough guide. These are consensus goals that should be individualized, and the ADA measures them 1 to 2 hours after the meal starts.

What can affect your result

  • Meal size, sugar and starch content, and how fast you ate it
  • Exact timing: whether the clock started at the first bite and the sample was drawn at 2 hours
  • Activity after the meal, since muscles use glucose
  • Illness, stress, surgery or injury
  • Medicines, including corticosteroids and diabetes medicines
  • Pregnancy, which has its own testing and goals
  • Sample handling: unspun blood loses glucose as cells use it
  • The size and makeup of the meal change the result: a large or sugary meal gives a higher number than a small, mixed one.
  • Drawing the sample earlier or later than 2 hours after the meal starts changes the result.
  • A sample that sits before the blood cells are separated can read falsely low, because the cells use up glucose in the tube.
  • Illness, surgery, injury and other physical stress raise glucose, as can some medicines (for example corticosteroids).
  • A fingerstick meter or sensor reads a different sample than the lab does, so the numbers may not match.

Taken about 2 hours after you start a normal meal, counted from the first bite rather than the last. Follow your lab's or clinician's instructions about what to eat. Reflects a single meal and changes within hours. For a 2 to 3 month average, look at A1c.

When to talk to a clinician

Contact the clinician who ordered the test today if your lab flagged the result as critical. ARUP uses below 55 or above 450 mg/dL (3.1 or 25 mmol/L), and other labs use somewhat different limits. Call 911 or your local emergency number for confusion, fainting or seizures, or for very high glucose with vomiting, belly pain, fast breathing or extreme drowsiness. If the result is 200 mg/dL (11.1 mmol/L) or higher and you also have extreme thirst, frequent urination or unexplained weight loss, see a clinician promptly.

Questions you could ask

  • Was this drawn 2 hours after the start of a meal, and which range is my lab comparing it with?
  • Would tracking my fasting glucose and A1c alongside this help?
  • Should we repeat this, or check a fasting glucose or an A1c?
  • Could what I ate, or when the sample was drawn, explain this result?
  • Could any of my medicines be raising my after-meal glucose?
  • Could the timing of my meal or how the sample was handled explain this?

Questions people ask

Is this the same as the 2-hour glucose on a glucose tolerance test?

No. This test follows a regular meal. A glucose tolerance test (OGTT) uses a measured sugar drink after an overnight fast and has its own cutoffs. Some reports use the words "2-hour postprandial" for the OGTT value, so check which test you had.

What number is normal 2 hours after eating?

There is no single standard, because meals differ. Mayo Clinic Laboratories lists 70 to 140 mg/dL (3.9 to 7.8 mmol/L) for a non-fasting serum glucose. The ADA goal for many adults with diabetes is a peak below 180 mg/dL (10.0 mmol/L), measured 1 to 2 hours after the meal starts. In pregnancy with diabetes the ADA 2-hour goal is below 120 mg/dL (6.7 mmol/L). Use the range printed on your own report, and ask your clinician which goal fits you.

Does a high 2-hour post-meal result mean I have diabetes?

Not by itself. A big meal, illness or stress can raise it. The ADA diagnoses diabetes using fasting glucose, a 2-hour value on a 75 g glucose tolerance test, A1c, or a random glucose of 200 mg/dL or higher with classic symptoms, and it usually needs two results in the diabetes range. Your clinician decides what to repeat.

Show the science and sources

Units

  • 1 mg/dL = 1 mg/dL
  • 1 mg/dL = 0.05551 mmol/L
  • 1 mg/dL = 0.01 g/L

Open the 2-Hour Post-Meal Glucose unit converter

For clinicians and researchers

A timed venous plasma or serum glucose, drawn about 2 hours after the start of an ordinary meal. Unlike an OGTT, the load isn't standardized, so results depend on meal composition, and no standardized diagnostic cutoffs exist for it (the ADA's only non-fasting criterion is a random glucose of 200 mg/dL or higher with classic symptoms). For the 75 g OGTT the 2-hour value is a separate marker with its own ADA and IDF categories. Note that the IDF uses the phrase "2-hour postprandial glucose" for the post-load value in one of its tables, so check the protocol on your report. Reference data for a non-fasting draw: Mayo Clinic Laboratories lists 70 to 140 mg/dL for random serum glucose from 1 year of age. In 153 healthy, nondiabetic people (7 to 80 years) wearing blinded sensors, mean glucose was 98 to 99 mg/dL (104 mg/dL in the oldest group), and the median time between 70 and 140 mg/dL was 96% (Shah 2019). Treatment goals in diabetes: the ADA 2026 Standards give a peak postprandial capillary plasma glucose below 180 mg/dL (10.0 mmol/L) for many nonpregnant adults, measured 1 to 2 hours after the start of the meal, and suggest paying attention to postprandial glucose when A1c is above goal despite on-target preprandial values. The IDF (2017) notes that postprandial glucose below 10 mmol/L (180 mg/dL) in most measurements may predict an A1c below 7% but does not replace it. In pregnancy with diabetes, the ADA goals are fasting below 95 mg/dL with either 1-hour postprandial below 140 or 2-hour postprandial below 120 mg/dL; preconception advice is 2-hour postprandial below 155 mg/dL. Glycolysis in unseparated samples lowers measured glucose, so per the ADA plasma must be separated immediately or the sample kept on ice.

LOINC 1521-4 (primary), 14761-1, 6689-4, 77677-3. Specimen: serum-or-plasma.

Sources

  1. Glucose, Random, Serum (test GLURA), Mayo Clinic Laboratories test catalog, Mayo Clinic Laboratories (read through the testcatalog.org mirror)
  2. Continuous Glucose Monitoring Profiles in Healthy Nondiabetic Participants: A Multicenter Prospective Study, Journal of Clinical Endocrinology & Metabolism (2019)
  3. 6. Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes-2026, American Diabetes Association (Diabetes Care) (2026)
  4. IDF Clinical Practice Recommendations for managing Type 2 Diabetes in Primary Care, International Diabetes Federation (2017)
  5. 15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes-2026, American Diabetes Association (Diabetes Care) (2026)
  6. Critical Values List (CORP-APPEND-0104A, Rev. 46), ARUP Laboratories (2026)
  7. Critical (Panic) Values, with adult reference intervals (document DX_TL_811850, 01/19/2024), Labcorp (2024)
  8. 2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2026, American Diabetes Association (Diabetes Care) (2026)
  9. Glucose (PubChem compound 5793), PubChem, National Library of Medicine

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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