Biomarker Lens

Common biomarkers

  • Hemoglobin
  • Glucose
  • ALT
  • Apolipoprotein B
  • C-Reactive Protein, Cardiac
  • Ferritin
  • Alb/Creat Ratio, Urine
  • Alkaline Phosphatase
  • FSH
  • T4,Free(Direct)

Biomarkers · Chemical

Glucose

A blood glucose test measures the glucose levels in your blood. Glucose is a type of sugar.

Blood Glucose Test, MedlinePlus, National Library of Medicine

The test measures the level of glucose, a type of sugar, in the blood. Insulin is the hormone that helps move glucose from the bloodstream into cells, where the body uses it for energy.

Also listed as
serum glucose, fasting glucose, blood glucose, blood sugar, plasma glucose, Glucose, Two-Hour Postprandial
Primary unit
mg/dL
LOINC codes
1504-0, 1521-4, 1514-9, 1518-0, 1507-3, 12638-3, 2345-7
Tests that measure Glucose
Quest Diagnostics 30, Labcorp 23

See why clinicians order the test

  • Clinicians most commonly order glucose testing to screen for and monitor prediabetes and diabetes.

    Condition: Prediabetes

  • Clinicians order the test to help find the cause of symptoms that suggest blood glucose is too high or too low.

    Goal: Blood sugar

  • Clinicians use the test to monitor side effects of certain medicines taken over the long term that can affect blood glucose.

  • Clinicians commonly order glucose testing between the 24th and 28th week of pregnancy to check for gestational diabetes.

  • Raised fasting glucose is one of the recognized risk factors clinicians use when assessing for metabolic syndrome.

    Condition: Metabolic syndrome

Read with companion markers

  • HDL

    Clinicians read fasting glucose with HDL cholesterol because raised glucose and lowered HDL both count among metabolic syndrome risk factors.

  • Triglycerides

    Clinicians read fasting glucose with triglycerides because raised levels of both count among the clustered risk factors of metabolic syndrome.

  • Hemoglobin A1c

    Clinicians often confirm a raised HbA1c with a repeat HbA1c or another diabetes test, usually fasting blood glucose or an oral glucose tolerance test.

Choose the right version

  • Hemoglobin A1cAlternative test

    The HbA1c test gives information about average blood glucose levels across the past 3 months from a single blood sample.

Check what can shift results

  • Condition

    • Problems with the pancreas or adrenal glands can raise blood glucose apart from diabetes, as can side effects of certain medicines.
  • Medicine

    • Certain types of medicines can cause high blood glucose in some people who take them.

Prepare for the test

  • A fasting blood glucose test or an oral glucose tolerance test requires fasting for at least eight hours beforehand.
  • When glucose is measured as part of a BMP or CMP panel, fasting may be required.

Each statement links to the source we wrote it from. Last updated October 19, 2026.

Ranges

Compare the reference ranges labs publish with guideline targets, diagnostic cut-offs, study-based ranges and practitioner targets. Move across the rows to check a value against each range, and open a source from the legend. How to read these ranges

Glucose, mg/dL

Labs
Cut-offs
  • Lab reference ranges2 labs
  • Diagnostic cut-offs3 cut-offs
All 5 published ranges, with sources

Lab reference ranges

Diagnostic cut-offs

Tests

Check the catalog code, specimen, method and preparation for every test that measures Glucose. Select up to five tests to compare them side by side.

Quest Diagnostics 30 tests

Single-analyte tests

  • Cardio IQ® Glucose 91947

    Serum · Fasting required · Turnaround Set up: Tues-Sat

    Method and collection
    Method
    Spectrophotometry (SP)
    Preparation
    Fasting required. Fasting is defined as no consumption of food or beverage other than water for at least 8 hours prior to collection.
    Collection
    Serum submissions must be separated from cells
    Reference notes
    65-99 mg/dL
    Quest Diagnostics catalog page
  • Glucose 483

    Serum · Fasting not stated · Turnaround Set up: Mon-Sat; Report available: 3 days

    Method and collection
    Method
    Spectrophotometry (SP)
    Preparation
    Fasting preferred. Fasting is defined as no consumption of food or beverage other than water for at least 8 hours before testing.
    Collection
    Serum and plasma submissions must be separated from cells
    Reference notes
    Fasting Reference Interval | 65-99 mg/dL Non-fasting Reference Interval | 65-139 mg/dL
    Quest Diagnostics catalog page
  • Glucose Tolerance Test, Postprandial/2-Hour 4637

    Plasma · Fasting not stated

    Method and collection
    Method
    Spectrophotometry (SP)
    Collection
    Specimen is obtained 2 hours following a meal. Serum and plasma submissions must be separated from cells.
    Reference notes
    <140 mg/dL
    Quest Diagnostics catalog page
  • Glucose, Gestational Screen (50g), 135 Cutoff 8477

    Plasma · No fasting · Turnaround Set up: Daily (Day shift); Report available: 3 days

    Method and collection
    Method
    Spectrophotometry (SP)
    Preparation
    Fasting is not required
    Collection
    The patient is given a 50 g dose of glucose and a single blood specimen is obtained one hour later. Serum and plasma submissions must be separated from cells. Note: The test should be performed between weeks 24 and 28 of gestation.
    Reference notes
    <135 mg/dL
    Quest Diagnostics catalog page
  • Glucose, Gestational Screen (50g), 140 Cutoff 19833

    Plasma · Fasting not stated

    Method and collection
    Method
    Spectrophotometry (SP)
    Collection
    The test should be performed between weeks 24 and 28 of gestation. The patient is given a 50 g dose of glucose and a single blood specimen is obtained one hour later. Fasting is not required. Note: Serum and plasma submissions must be separated from cells.
    Reference notes
    <140 mg/dL
    Quest Diagnostics catalog page
  • Glucose, Random 8917

    Serum · Fasting not stated · Turnaround Set up: Mon-Sat; Report available: 3 days

    Method and collection
    Method
    Spectrophotometry (SP)
    Collection
    Note: Serum and plasma submissions must be separated from cells
    Reference notes
    <140 mg/dL
    Quest Diagnostics catalog page

Panels that include this biomarker

  • Diabetes and ASCVD Risk Panel with Scores 92062

    7 analytes · Serum · Fasting not stated

    Method and collection
    Method
    Turbidimetric Inhibition Immunoassay • Spectrophotometry (SP)
    Preparation
    If a cholesterol measurement is to be performed along with triglycerides, but not part of a lipid panel, then the patient should be fasting 9-12 hours prior to collection. If the cholesterol is ordered as part of a lipid panel, then a fasting sample is not required. The assay manufacturer Beckman Coulter advises: N-Acetyl Cysteine (NAC), when administered in therapeutic concentrations (for the treatment of acetaminophen overdose), has been determined to interfere with assays for cholesterol and uric acid where "NAC interference may lead to falsely low results." According to Beckman Coulter, the NAC interference should be insignificant by 12 hours after completion of the initial loading dose of an IV infusion treatment regimen consisting of an initial loading dose of 150 mg/kg administered over 1 hour, a second dose of 50 mg/kg administered over 4 hours and a third dose of 100 mg/kg administered over 16 hours.
    Collection
    For risk calculations to be performed, the following patient-specific information must be provided at the time of order: Age: Years Gender: M (for male) or F (for female) Race - African American: Y (for yes) or N (for no) Systolic Blood Pressure: mmHg Treatment for High B.P.: Y (for yes) or N (for no) Diabetes Status: Y (for yes) or N (for no) Smoking Status: Y (for yes) or N (for no)
    Reference notes
    See individual tests
    Quest Diagnostics catalog page
  • Diabetes Risk Panel with Score 92027

    7 analytes · Serum · Fasting not stated

    Method and collection
    Method
    Turbidimetric Inhibition Immunoassay • Spectrophotometry (SP)
    Preparation
    If a cholesterol measurement is to be performed along with triglycerides, but not part of a lipid panel, then the patient should be fasting 9-12 hours prior to collection. If the cholesterol is ordered as part of a lipid panel, then a fasting sample is not required. The assay manufacturer Beckman Coulter advises: N-Acetyl Cysteine (NAC), when administered in therapeutic concentrations (for the treatment of acetaminophen overdose), has been determined to interfere with assays for cholesterol and uric acid where "NAC interference may lead to falsely low results." According to Beckman Coulter, the NAC interference should be insignificant by 12 hours after completion of the initial loading dose of an IV infusion treatment regimen consisting of an initial loading dose of 150 mg/kg administered over 1 hour, a second dose of 50 mg/kg administered over 4 hours and a third dose of 100 mg/kg administered over 16 hours.
    Collection
    For risk calculations to be performed, the following patient-specific information must be provided at the time of order: Age: Years Gender: M (for male) or F (for female)
    Reference notes
    See individual tests
    Quest Diagnostics catalog page
  • Metabolic Syndrome and Glucose Control Including Insulin 91398

    7 analytes · Serum · Fasting not stated

    Method and collection
    Method
    Chromatography/Mass Spectrometry • Spectrophotometry (SP)
    Preparation
    If a cholesterol measurement is to be performed along with triglycerides, but not part of a lipid panel, then the patient should be fasting 9-12 hours prior to collection. If the cholesterol is ordered as part of a lipid panel, then a fasting sample is not required. The assay manufacturer Beckman Coulter advises: N-Acetyl Cysteine (NAC), when administered in therapeutic concentrations (for the treatment of acetaminophen overdose), has been determined to interfere with assays for cholesterol and uric acid where "NAC interference may lead to falsely low results." According to Beckman Coulter, the NAC interference should be insignificant by 12 hours after completion of the initial loading dose of an IV infusion treatment regimen consisting of an initial loading dose of 150 mg/kg administered over 1 hour, a second dose of 50 mg/kg administered over 4 hours and a third dose of 100 mg/kg administered over 16 hours.
    Reference notes
    See Laboratory Report
    Quest Diagnostics catalog page
  • NAFLD Fibrosis Score 91979

    7 analytes · Serum · Fasting not stated

    Method and collection
    Method
    Spectrophotometry (SP) • Electronic Sizing and Counting/Cytometry/Microscopy
    Preparation
    Fasting preferred. Fasting is defined as no consumption of food or beverage other than water for at least 8 hours before testing.
    Collection
    For risk calculations to be performed, the following patient-specific information must be provided at the time of order: Age: Years Gender: M (for male) or F (for female) Height Feet: Feet Height Inches: Inches Weight: lbs. Diabetes Status: Y (for yes) or N (for no)
    Reference notes
    See Laboratory Report
    Quest Diagnostics catalog page
  • Basic Metabolic Panel without Calcium 34388

    8 analytes · Serum · Fasting not stated

    Method and collection
    Method
    See individual tests
    Preparation
    Fasting specimen is preferred
    Reference notes
    See Laboratory Report
    Quest Diagnostics catalog page

Labcorp 23 tests

Single-analyte tests

  • Gestational Diabetes Screen (ACOG Recommendations) 102277

    Serum · Fasting not stated · Turnaround Within 1 day

    Method and collection
    Method
    Enzymatic
    Preparation
    None; glucose challenge is administered without regard to time of day or time of last meal.
    Collection
    Note: A fasting blood sample is not required. Draw one hour specimen after a 50-gram glucose challenge. The patient should remain seated and not smoke throughout the test. Submit 1 mL serum or plasma for one-hour specimen. Separate serum or plasma from cells within 45 minutes of venipuncture. Gray-top tubes only, may be submitted without centrifugation. Label tube with patient's name and collection time interval (i.e., one-hour).
    Reference notes
    70−139 mg/dL
    Labcorp catalog page
  • Glucose 001032

    Serum · Fasting not stated · Turnaround Within 1 day

    Method and collection
    Method
    Enzymatic
    Preparation
    Blood should be drawn in the morning after an overnight fast. Per the American Diabetes Association (ADA), fasting is defined as no caloric intake for at least eight hours.1
    Collection
    Separate serum or plasma from cells within 45 minutes of collection. Label specimen as serum or lithium heparin plasma.
    Reference notes
    70−99 mg/dL
    Labcorp catalog page
  • Glucose, Two-hour Postprandial 002022

    Serum · Fasting not stated · Turnaround Within 1 day

    Method and collection
    Method
    Enzymatic
    Preparation
    Adequate meal or 75-gram glucose load two hours before two-hour postprandial glucose, as specified by the patient's physician. Patient is allowed usual meal (breakfast or lunch). Patient must complete meal within 15 to 20 minutes.
    Collection
    Collect specimen two hours from the beginning of meal. Separate serum or plasma from cells within 45 minutes of venipuncture. Gray-top tubes only, may be submitted without centrifugation. Label tube with patient's name and collection time.
    Reference notes
    65−139 mg/dL
    Labcorp catalog page

Panels that include this biomarker

  • Gestational Glucose Tolerance Screening and Diagnostic Test (Two-hour, ADA Recommendations) 101000

    2 analytes · Serum · Fasting not stated · Turnaround Within1 day

    Method and collection
    Method
    Enzymatic
    Preparation
    Patient should be active and eat a regular diet that includes at least 150 grams of carbohydrate daily for three days prior to the test. The patient should be instructed not to eat or drink anything except water for at least eight hours and not more than 14 hours before the test. Patients should also be advised to discontinue, whenever possible, all nonessential medication that can affect glucose metabolism at least three days before testing.
    Collection
    Draw a fasting blood sample before administering glucose. Administer a 75-gram glucose and draw blood after one hour and two hours. The patient should remain seated throughout the test. Submit 1 mL serum or plasma for fasting, one-hour, and two-hour specimens. Separate serum or plasma from cells within 45 minutes of venipuncture. Gray-top tubes only, may be submitted without centrifugation. Label each tube with the patient's name and collection time interval (i.e,, fasting, one-hour, and two-hour).
    Reference notes
    See table. Specimen (Two-hour GGT Test)* Range (mg/dL) *A positive diagnosis requires that only one of the high thresholds be exceeded. Fasting 70−91 One-hour 70−179 Two-hour 70−152
    Labcorp catalog page
  • Glucose Tolerance Test (GTT), Two-hour (Oral WHO Protocol) 101200

    2 analytes · Serum · Fasting not stated · Turnaround Within1 day

    Method and collection
    Method
    Enzymatic
    Preparation
    Patient should be active and eat a regular diet that includes at least 150 grams of carbohydrate daily for three days prior to the test. Patient should be instructed not to eat or drink anything except water for at least eight hours and not more than 14 hours before the test. Patients should also be advised to discontinue, whenever possible, all nonessential medication that can affect glucose metabolism at least three days before testing.
    Collection
    Draw a fasting blood sample before administering glucose. Administer a 75-gram glucose and draw blood after two hours. The patient should remain seated throughout the test. Submit 1 mL serum or plasma for fasting and two-hour specimens. Separate serum or plasma from cells within 45 minutes of venipuncture. Gray-top tubes only, may be submitted without centrifugation. Label each tube with the patient's name and collection time interval. (ie, fasting and two-hour).
    Labcorp catalog page
  • Metabolic Syndrome Profile 335884

    3 analytes · Serum · Fasting not stated · Turnaround Within 1 day

    Method and collection
    Method
    Enzymatic
    Preparation
    Patient should be fasting for 12 to 14 hours and on a stable diet for two weeks prior to blood collection.
    Collection
    Separate serum or plasma from cells within 45 minutes of collection. Label gray-top tube as plasma.
    Labcorp catalog page
  • Gestational Glucose Tolerance Diagnostic Test (Three-hour, ACOG Recommendations) 102004

    4 analytes · Serum · Fasting not stated · Turnaround Within 1 day

    Method and collection
    Method
    Enzymatic
    Preparation
    For three days prior to the test, patients should eat an unrestricted diet of 150 or more grams of carbohydrate and be permitted unrestricted physical activity. Patients should be instructed to eat and drink nothing except water for at least eight hours and not more than 14 hours before the test. Patients should also be advised to discontinue, whenever possible, all nonessential medication that can affect glucose metabolism at least three days before testing.
    Collection
    Draw a fasting blood sugar before administering 100-gram glucose, and draw blood at one, two, and three hours. The subject should remain seated and not smoke throughout the test. Submit 1 mL serum or plasma for fasting, one-hour, two-hour, and three-hour specimens. Separate serum or plasma from cells within 45 minutes of venipuncture. Gray-top tubes only, may be submitted without centrifugation. Label each tube with patient's name and collection time interval (i.e., fasting, one-hour, two-hour, and three-hour).
    Reference notes
    See table. Specimen* Plasma or Serum Glucose Level (Carpenter and Coustan Conversion) Plasma Glucose Level (National Diabetes Data Group Conversion) *The diagnosis of GDM can be made based on the result of the 100-gram, three-hour oral glucose tolerance test, for which there is evidence that treatment improves outcome. Either the plasma or serum glucose level established by Carpenter and Coustan or the plasma level designated by the National Diabetes Data Group is appropriate to use. A positive diagnosis requires that two or more high thresholds be exceeded. The Carpenter and Coustan conversion is used to establish Labcorp reference intervals. Fasting 70−94 mg/dL 70−105 mg/dL One-hour 70−179 mg/dL 70−190 mg/dL Two-hour 70−154 mg/dL 70−165 mg/dL Three-hour 70−139 mg/dL 70−145 mg/dL
    Labcorp catalog page
  • Lactose Tolerance Test 046300

    5 analytes · Plasma · Fasting not stated · Turnaround Within 1 day

    Method and collection
    Method
    Enzymatic
    Preparation
    Patient should fast for eight hours before testing. No smoking or gum chewing allowed during test. Patient is encouraged to drink a moderate amount, one to two glasses of water during test. Patient should remain seated or in bed during test.
    Collection
    Draw fasting sample prior to lactose administration. Give lactose according to the following: • Children up to 12 years: 2 g/kg body weight with a maximum of 50 g in 250 mL water. • Adults: 50 g in 250 mL water Collect specimens at 30, 60, 90, and 120 minutes following lactose administration. Label each tube with the patient's name and time of drawing according to the following: The first tube should be labeled with the "patient's name," "fasting," and the time of the draw. The remaining four tubes should be labeled with the "patient's name" and the time of the draw.
    Labcorp catalog page

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Goals and conditions

We link Glucose to these goals and conditions from named guidelines and studies.

Sources

Check the guidelines, studies and lab catalogs behind every range and link on this page. Open a source to see each claim it backs.

Clinical guidelines

Lab catalogs

Reference sources

Codes and registries

Verify these ranges and sources

We compile this page from named laboratory catalogs, guidelines and studies. Labs calculate reference intervals from the people they test, for one assay method and one population group, so an interval describes that population rather than an optimal target.

Interpret your own results with a licensed clinician, or track your lab history and health goals in Aumnivida.

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