Glucose Tolerance Testing

DIAGNOSIS OF DIABETES: Glucose Tolerance Testing

Policy Tech Version 13

TESTING OPTIONS:

A. Random plasma glucose

B. Fasting plasma glucose (Minimum of 8 hours without caloric intake)

C. Two Hour Modified Glucose Tolerance Test (Not recommended for routine clinical use. Use with high risk populations such as children with cystic fibrosis.(Performed at Akron Campus - In-Patient and Outpatient Labs, Hudson and Mahoning Valley)

D. Gestational Diabetes Screening Test (Performed at Akron Campus- Outpatient Labs, Hudson and Mahoning Valley)

E. Gestational Diabetes Confirmation Test (Performed at Akron Campus - Outpatient Labs, Hudson and Mahoning Valley)

Specimen Requirements for specimens sent to the Laboratory: Lithium Heparin; send specimen to laboratory immediately.

PROCEDURES

A. Random - Draw appropriate specimen and deliver to the laboratory. See Specimen Requirements section.

B.  Fasting Plasma Glucose - If a Fasting Plasma Glucose is ordered on an Inpatient without a specified time, assume that it is for the following AM. If the time is for anything other than AM call the patient care unit and determine if the patient is truly fasting and confirm when the specimen is to be collected. On an Outpatient confirm the fasting status with the patient and/or parent. Order a Glucose (Lab code GLU) and record fasting when appropriate in the order comment. Draw the appropriate specimen and immediately send to the lab for analysis.

C. Two Hour Modified Glucose -Order a Glucose, 2 Hr Challenge (LabCode GL2HR).

this procedure requires two specimens to be sent to the laboratory; a fasting specimen and a two hour post glucose drink specimen.

1. A fasting blood glucose is drawn which will be sent to the laboratory. (See specimen requirements above)
2. Prior to administering Azer Scientific Glucose Drink, a glucometer is used to assess the fasting state of the patient on a drop of specimen from the fasting draw. The remainder of the specimen is then immediately sent to the lab for analysis. A fasting glucose greater than 125 mg/dl requires a call to the patient=s physician before continuing with the procedure. Do not administer the Azer Scientific Glucose Drink without contacting the appropriate individual.
3. The patient is given a dose of glucose corresponding to his or her weight. 1.75 grams of glucose are given per kilogram of body weight up to a maximum of 75g or 218 ml. (See Glucose Dosage Chart.) The Azer Scientific Glucose Drink should be measured using a graduated cylinder. The amount remaining in the bottle should be discarded once the bottle has been opened.
4. A second blood specimen is then taken at two hours and immediately sent to the lab for analysis.
5. Food, drink, and smoking are prohibited and limited activity is recommended for the duration of a glucose tolerance test. (Inpatients - Be sure to place or have nursing place a NPO sign on the patient=s bed throughout the duration of the test.)

Gestational Diabetes Screen - This is not a Glucose Tolerance Test and thus does not require that the patient be fasting. Order a MFM Glucose Challenge, 1 Hr (Lab Code MFMGL). The laboratory does not receive a fasting specimen, the lab is only sent theone hour post glucose drink specimen.

Prior to giving Azer Scientific Glucose Drink, a blood specimen should be tested on a glucometer for assurance that the level is less than 200 mg/dl. Glucose levels equal to or greater than 200 mg/dl can be diagnostic for Diabetes. If the glucose level is equal to or greater than 200 mg/dl, the physician should be contacted before continuing with the procedure.

1. Glucose by glucometer is performed, see above paragraph.
2. Patient is given 50g of Glucose or 148 ml of the Azer Scientific Glucose Drink
3. Blood is drawn and sent to the laboratory one hour later. See the specimen requirements section for specimen to collect.

E. Gestational Diabetes Confirmation Test -  Order a Gestational 3 Hr Challenge (Lab Code MG3HR). The laboratory will be sent a fasting specimen, a 1 hour post, 2 hour post and 3 hour post glucose drink specimen. See the specimen requirements section to collect.

After an abnormal gestational diabetes screening test, the physician may order a Glucose Tolerance Test. Prior to giving Azer Scientific Glucose Drink, the fasting specimen should be tested on a Glucose meter for assurance that the level is less than 125 mg/dl. If the level is above 125 mg/dl, the physician should be contacted before continuing with the procedure.

1. A fasting blood glucose is drawn which will be sent to the laboratory. (See specimen requirements above)
2. A glucose by glucometer is performed on the fasting specimen.
3. If the level is less than 125 mg/dl, then 100g of Glucose or 296ml of Azer Glucose Drink is given.
4. Specimens are drawn Fasting, 1 Hour, 2 Hour and 3 Hour.

NOTE:If the patient should vomit within the 15 minutes of drinking the glucose drink, call the physician and notify him that the procedure is being cancelled and will need to be reordered. If more than 15 minutes has passed continue the procedure and notify CCL to put a comment in when they result the test.

REAGENTS 1.Azer Scientific 100 Glucose Tolerance Test Drink One bottle = 296 ml = 100 grams of glucose, .34 gram/ml The Glucose beverage for inpatients will be stored in the Locust Out Patient Lab. If the glucose solution is needed before the outpatient lab is open, someone will have to go to the OPL to obtain the solution, IT IS NOT TO BE STORED IN ANY OF THE REFRIGERATORS IN THE LAB. The plastic graduated cylinders used to measure the Azer Scientific Glucose Drink. The plastic graduated cylinders should be sent back to the main lab for washing after each use. REFERENCES 1.Standards of Medical Care in Diabetes - 2013, Diabetes Care Volume 36, Supplement 1, January 2013.