Available Stat

No

Performing Lab

Parnassus, Mission Bay & Mt. Zion Chemistry

Performed

Parnassus ACC 0730-1330 weekdays. 
Mission Bay 0700-1330 weekdays. 
Mount Zion 2230 Post St. 0800-1330 weekdays.

Methodology

Hexokinase/G-6-PDH
 

Additional Information

Glucose tolerance screening for  gestational diabetes mellitus (GDM) may be performed as a one step approach or as a two step approach. This "3 hour 100 gram glucose tolerance test, pregnancy" is the second test in the two step screening approach for GDM. For the first test in the two step screening approach, see the "1 hour 50 gram glucose loading screen." A positive diagnosis in this second step test requires that two or more reference range thresholds be met or exceeded. For a discussion on the reference range for this test, see UpToDate section on "Screening for and diagnosis of diabetes mellitus during pregnancy." 

For the one step approach to screening for GDM, see " 2 Hour, 75 gram Glucose Tolerance Test, Pregnant."

"Glucose tolerance beverages are available in 100 g bottles (10 g/fl. oz. at 10
oz.) at ACC, and 100 g and 50 g bottles (10 g/fl. oz., 5 g/fl. oz.both 10 oz.) at
Post St.

Source of reference range: UpToDate and the 4th International Workshop on Gestational Diabetes

Synonyms

  • Diabetes mellitus
  • OGTP
  • 3GT60
  • 3GT120
  • 3GT180

Patient Preparation

The patient should be instructed by the care-giver to eat a normal diet containing at least 150 g of carbohydrate and carry out normal physical activity for at least 3 days prior to the morning of the test, which is administered after an 8-14 hour. fast.

Sample Type

Plasma

Collect

Gray top

Amount to Collect

1 mL blood

Preferred Volume

0.5 mL plasma

Minimum Volume

0.2 mL plasma

Remarks

The patient should be seated for the test and should not smoke.

Collect all samples in Gray top tubes

An 8-14 hour fast is required to perform this test. If the patient did not fast for this period, cancel the test and inform the patient to return after fasting for the required time.

Obtain a fasting sample and send to lab for stat testing and follow the 3 hour glucose tolerance testing procedure for the remaining samples.
 
Note: The fasting glucose result must be <110 mg/dL to proceed with the glucose tolerance test. If the fasting glucose result is 110 mg/dL or higher, cancel the glucose tolerance test.

Stability (from collection to initiation)

Room temperature 2 days, refrigerated 7 days, frozen at -20C 3 months
 

Test Code

OGTP, 3GT60, 3GT120, 3GT180

Test Group

Glucose

Performing Lab

Parnassus, Mission Bay & Mt. Zion Chemistry

Preferred Volume

0.5 mL plasma

Minimum Volume

0.2 mL plasma

Stability (from collection to initiation)

Room temperature 2 days, refrigerated 7 days, frozen at -20C 3 months
 

Units

mg/dL

Reference Interval

Fasting 70-94 mg/dL
1 hour (post glucose) < 180 mg/dL
2 hour (post glucose) < 155 mg/dL
3 hour (post glucose) < 140 mg/dL

Additional Information

Glucose tolerance screening for  gestational diabetes mellitus (GDM) may be performed as a one step approach or as a two step approach. This "3 hour 100 gram glucose tolerance test, pregnancy" is the second test in the two step screening approach for GDM. For the first test in the two step screening approach, see the "1 hour 50 gram glucose loading screen." A positive diagnosis in this second step test requires that two or more reference range thresholds be met or exceeded. For a discussion on the reference range for this test, see UpToDate section on "Screening for and diagnosis of diabetes mellitus during pregnancy." 

For the one step approach to screening for GDM, see " 2 Hour, 75 gram Glucose Tolerance Test, Pregnant."

"Glucose tolerance beverages are available in 100 g bottles (10 g/fl. oz. at 10
oz.) at ACC, and 100 g and 50 g bottles (10 g/fl. oz., 5 g/fl. oz.both 10 oz.) at
Post St.

Source of reference range: UpToDate and the 4th International Workshop on Gestational Diabetes

CPT Codes

82947

Available Stat

No

Test Code

OGTP, 3GT60, 3GT120, 3GT180

Test Group

Glucose

Performing Lab

Parnassus, Mission Bay & Mt. Zion Chemistry

Performed

Parnassus ACC 0730-1330 weekdays. 
Mission Bay 0700-1330 weekdays. 
Mount Zion 2230 Post St. 0800-1330 weekdays.

Methodology

Hexokinase/G-6-PDH
 

Patient Preparation

The patient should be instructed by the care-giver to eat a normal diet containing at least 150 g of carbohydrate and carry out normal physical activity for at least 3 days prior to the morning of the test, which is administered after an 8-14 hour. fast.

Remarks

The patient should be seated for the test and should not smoke.

Collect all samples in Gray top tubes

An 8-14 hour fast is required to perform this test. If the patient did not fast for this period, cancel the test and inform the patient to return after fasting for the required time.

Obtain a fasting sample and send to lab for stat testing and follow the 3 hour glucose tolerance testing procedure for the remaining samples.
 
Note: The fasting glucose result must be <110 mg/dL to proceed with the glucose tolerance test. If the fasting glucose result is 110 mg/dL or higher, cancel the glucose tolerance test.

Collect

Gray top

Amount to Collect

1 mL blood

Sample Type

Plasma

Preferred Volume

0.5 mL plasma

Minimum Volume

0.2 mL plasma

Units

mg/dL

Reference Interval

Fasting 70-94 mg/dL
1 hour (post glucose) < 180 mg/dL
2 hour (post glucose) < 155 mg/dL
3 hour (post glucose) < 140 mg/dL

Synonyms

  • Diabetes mellitus
  • OGTP
  • 3GT60
  • 3GT120
  • 3GT180

Stability (from collection to initiation)

Room temperature 2 days, refrigerated 7 days, frozen at -20C 3 months
 

Additional Information

Glucose tolerance screening for  gestational diabetes mellitus (GDM) may be performed as a one step approach or as a two step approach. This "3 hour 100 gram glucose tolerance test, pregnancy" is the second test in the two step screening approach for GDM. For the first test in the two step screening approach, see the "1 hour 50 gram glucose loading screen." A positive diagnosis in this second step test requires that two or more reference range thresholds be met or exceeded. For a discussion on the reference range for this test, see UpToDate section on "Screening for and diagnosis of diabetes mellitus during pregnancy." 

For the one step approach to screening for GDM, see " 2 Hour, 75 gram Glucose Tolerance Test, Pregnant."

"Glucose tolerance beverages are available in 100 g bottles (10 g/fl. oz. at 10
oz.) at ACC, and 100 g and 50 g bottles (10 g/fl. oz., 5 g/fl. oz.both 10 oz.) at
Post St.

Source of reference range: UpToDate and the 4th International Workshop on Gestational Diabetes

CPT Codes

82947
Ordering

Available Stat

No

Performing Lab

Parnassus, Mission Bay & Mt. Zion Chemistry

Performed

Parnassus ACC 0730-1330 weekdays. 
Mission Bay 0700-1330 weekdays. 
Mount Zion 2230 Post St. 0800-1330 weekdays.

Methodology

Hexokinase/G-6-PDH
 

Additional Information

Glucose tolerance screening for  gestational diabetes mellitus (GDM) may be performed as a one step approach or as a two step approach. This "3 hour 100 gram glucose tolerance test, pregnancy" is the second test in the two step screening approach for GDM. For the first test in the two step screening approach, see the "1 hour 50 gram glucose loading screen." A positive diagnosis in this second step test requires that two or more reference range thresholds be met or exceeded. For a discussion on the reference range for this test, see UpToDate section on "Screening for and diagnosis of diabetes mellitus during pregnancy." 

For the one step approach to screening for GDM, see " 2 Hour, 75 gram Glucose Tolerance Test, Pregnant."

"Glucose tolerance beverages are available in 100 g bottles (10 g/fl. oz. at 10
oz.) at ACC, and 100 g and 50 g bottles (10 g/fl. oz., 5 g/fl. oz.both 10 oz.) at
Post St.

Source of reference range: UpToDate and the 4th International Workshop on Gestational Diabetes

Synonyms

  • Diabetes mellitus
  • OGTP
  • 3GT60
  • 3GT120
  • 3GT180
Collection

Patient Preparation

The patient should be instructed by the care-giver to eat a normal diet containing at least 150 g of carbohydrate and carry out normal physical activity for at least 3 days prior to the morning of the test, which is administered after an 8-14 hour. fast.

Sample Type

Plasma

Collect

Gray top

Amount to Collect

1 mL blood

Preferred Volume

0.5 mL plasma

Minimum Volume

0.2 mL plasma

Remarks

The patient should be seated for the test and should not smoke.

Collect all samples in Gray top tubes

An 8-14 hour fast is required to perform this test. If the patient did not fast for this period, cancel the test and inform the patient to return after fasting for the required time.

Obtain a fasting sample and send to lab for stat testing and follow the 3 hour glucose tolerance testing procedure for the remaining samples.
 
Note: The fasting glucose result must be <110 mg/dL to proceed with the glucose tolerance test. If the fasting glucose result is 110 mg/dL or higher, cancel the glucose tolerance test.

Stability (from collection to initiation)

Room temperature 2 days, refrigerated 7 days, frozen at -20C 3 months
 
Processing

Test Code

OGTP, 3GT60, 3GT120, 3GT180

Test Group

Glucose

Performing Lab

Parnassus, Mission Bay & Mt. Zion Chemistry

Preferred Volume

0.5 mL plasma

Minimum Volume

0.2 mL plasma

Stability (from collection to initiation)

Room temperature 2 days, refrigerated 7 days, frozen at -20C 3 months
 
Result Interpretation

Units

mg/dL

Reference Interval

Fasting 70-94 mg/dL
1 hour (post glucose) < 180 mg/dL
2 hour (post glucose) < 155 mg/dL
3 hour (post glucose) < 140 mg/dL

Additional Information

Glucose tolerance screening for  gestational diabetes mellitus (GDM) may be performed as a one step approach or as a two step approach. This "3 hour 100 gram glucose tolerance test, pregnancy" is the second test in the two step screening approach for GDM. For the first test in the two step screening approach, see the "1 hour 50 gram glucose loading screen." A positive diagnosis in this second step test requires that two or more reference range thresholds be met or exceeded. For a discussion on the reference range for this test, see UpToDate section on "Screening for and diagnosis of diabetes mellitus during pregnancy." 

For the one step approach to screening for GDM, see " 2 Hour, 75 gram Glucose Tolerance Test, Pregnant."

"Glucose tolerance beverages are available in 100 g bottles (10 g/fl. oz. at 10
oz.) at ACC, and 100 g and 50 g bottles (10 g/fl. oz., 5 g/fl. oz.both 10 oz.) at
Post St.

Source of reference range: UpToDate and the 4th International Workshop on Gestational Diabetes
Administrative

CPT Codes

82947
Complete View

Available Stat

No

Test Code

OGTP, 3GT60, 3GT120, 3GT180

Test Group

Glucose

Performing Lab

Parnassus, Mission Bay & Mt. Zion Chemistry

Performed

Parnassus ACC 0730-1330 weekdays. 
Mission Bay 0700-1330 weekdays. 
Mount Zion 2230 Post St. 0800-1330 weekdays.

Methodology

Hexokinase/G-6-PDH
 

Patient Preparation

The patient should be instructed by the care-giver to eat a normal diet containing at least 150 g of carbohydrate and carry out normal physical activity for at least 3 days prior to the morning of the test, which is administered after an 8-14 hour. fast.

Remarks

The patient should be seated for the test and should not smoke.

Collect all samples in Gray top tubes

An 8-14 hour fast is required to perform this test. If the patient did not fast for this period, cancel the test and inform the patient to return after fasting for the required time.

Obtain a fasting sample and send to lab for stat testing and follow the 3 hour glucose tolerance testing procedure for the remaining samples.
 
Note: The fasting glucose result must be <110 mg/dL to proceed with the glucose tolerance test. If the fasting glucose result is 110 mg/dL or higher, cancel the glucose tolerance test.

Collect

Gray top

Amount to Collect

1 mL blood

Sample Type

Plasma

Preferred Volume

0.5 mL plasma

Minimum Volume

0.2 mL plasma

Units

mg/dL

Reference Interval

Fasting 70-94 mg/dL
1 hour (post glucose) < 180 mg/dL
2 hour (post glucose) < 155 mg/dL
3 hour (post glucose) < 140 mg/dL

Synonyms

  • Diabetes mellitus
  • OGTP
  • 3GT60
  • 3GT120
  • 3GT180

Stability (from collection to initiation)

Room temperature 2 days, refrigerated 7 days, frozen at -20C 3 months
 

Additional Information

Glucose tolerance screening for  gestational diabetes mellitus (GDM) may be performed as a one step approach or as a two step approach. This "3 hour 100 gram glucose tolerance test, pregnancy" is the second test in the two step screening approach for GDM. For the first test in the two step screening approach, see the "1 hour 50 gram glucose loading screen." A positive diagnosis in this second step test requires that two or more reference range thresholds be met or exceeded. For a discussion on the reference range for this test, see UpToDate section on "Screening for and diagnosis of diabetes mellitus during pregnancy." 

For the one step approach to screening for GDM, see " 2 Hour, 75 gram Glucose Tolerance Test, Pregnant."

"Glucose tolerance beverages are available in 100 g bottles (10 g/fl. oz. at 10
oz.) at ACC, and 100 g and 50 g bottles (10 g/fl. oz., 5 g/fl. oz.both 10 oz.) at
Post St.

Source of reference range: UpToDate and the 4th International Workshop on Gestational Diabetes

CPT Codes

82947

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