3-Hour Glucose Test Results

What is a 3-Hour Glucose Test Results Chart?

A 3-hour glucose tolerance test, also commonly known as the oral glucose tolerance test, is a well-utilized medical tool utilized by healthcare professionals to measure the patient's response to sugar and acts as a secondary screening process for gestational diabetes. For patients whose blood sugar sits between 140 mg/dL to less than 190 mg/dL in a 1-hour glucose tolerance test, further intervention is required. 

If the patient has a suspicious value during the 1-hour testing, this particular test helps rule out a dangerous prenatal diabetes development called gestational diabetes. The development of life-threatening preeclampsia is a risk derived from gestational diabetes. Hence, this tests immense value during the second trimester. 

This straightforward test involves a fasting period of 8 hours. Before administering a sugary drink containing 100 grams of glucose, blood sugar levels are taken. The patient is then to wait one hour after consumption before the next sample is taken. This occurs twice more in one-hour increments, meaning a total of 4 blood samples are taken for analysis, and no other food or drink is to be eaten during the 3-hour testing period. It is recommended that patients fast overnight and conduct the test first thing in the morning. 

A clear and concise charting tool like this helps to collate the results and compare them against the parameters of typical blood sugar levels, helping in the important diagnosis of gestational diabetes. The easy-to-use and easy-to-store chart makes this invaluable test a streamlined experience so that all further interventions can be collated, and the patient can access their results on Carepatron's centralized workspace through the free patient portal.

How Does It Work?

Step One: Gather your Resources

An easy-to-access and user-friendly chart for recording and analyzing the 3-hour glucose test results is key in any healthcare practice. Ensure you have your free printable 3-hour glucose test result chart on hand by simply clicking the “Download Template” button or keyword search “3-hour glucose test result chart” on the extensive database in Carepatrons template library.

Step Two: Collate Essential Information

Fill in the patient's key details and relevant medical history as well as symptoms and gestational period. Highlight if the patient falls under any of the ‘at risk’ categories and include the 1 hour glucose tolerance test result that indicated the need for this further testing.

Step Three: Conduct Testing

• Communicate to your patient that there needs to be an 8-hour fast before their scheduled appointment at a hematology lab. Small sips of water are permissible.
• When they first arrive blood will be drawn, and then the glucose drink will be offered. This needs to be consumed in five minutes or less.
• After an hour, blood levels will be taken again, and this process will repeat in one-hour increments till there are 4 total samples. No food or drink will be consumed during this 3-hour testing period, and smoking and exercise are also undesirable.

Step Four: Record and Analyze Results

Once blood test results are returned from the laboratory, fill in all sections of the glucose test result chart against the appropriate testing increments. The recommended parameters are then compared to your patient's results, and a diagnosis of gestational diabetes can then be formed. Use this same form to conveniently make further treatment suggestions and share with the appropriate specialists to assist the patient in the management of their condition.

Step Five: Store the Template Securely

After reviewing the results and hosting a consultation with your patient, you need to secure the 3-hour glucose test results chart so that access is only granted to relevant parties. Ensure this by utilizing Carepatrons HIPAA-compliant free patient records software. Here, all relevant medical records can be safely stored and collated for ease and security.

When Would You Use This Test?

A 3-hour glucose test, also known as a 3-hour oral glucose tolerance test (OGTT) is an easy and relatively non-intrusive test that can be used in multiple scenarios:

Gestational Diabetes Screening

If the pregnant patient sits outside of the normal parameters in a 1-hour glucose tolerance test, this more comprehensive screening test is utilized to help determine whether or not the prenatal condition is present and poses any risk. This screening typically occurs between the 24th and 28th week yet high-risk populations may receive this test earlier.

High Risk for Gestational Diabetes

Women who are part of the high-risk population for the development of this type of diabetes are advised strongly to engage in this testing process. Individuals with a family history of diabetes, high body mass index, or a previous pregnancy that caused the development of gestational diabetes are all patients who should receive this test prior to the second trimester.

Confirming Diagnosis

This test is paramount in the follow-up steps to an abnormal result during the 1 hour glucose tolerance test as it helps solidify the diagnosis. It is a more detailed assessment of how the patient processes glucose over time and helps to illustrate the difference in glycolic control. This test can be used to confidently make a distinction between gestational diabetes and normal changes in blood sugar through pregnancy.

What Do the Results Mean?

The metabolization of glucose can be analyzed over the four key time points of testing (fasting, 1 hour, 2 hours, and 3 hours) and compared to the recommended parameters for each period or identified as part of the abnormal figures section. Below are the parameters indicating abnormal blood values for the 3-hour, 100-gram oral glucose tolerance test: 

• Fasting:  Abnormal blood glucose levels: greater than 95 mg/dL (5.3 mmol/L)
• 1 Hour Post Drink:  Abnormal blood glucose levels: greater than 180 mg/dL (10 mmol/L)
• 2 Hours Post Drink:  Abnormal blood glucose levels: greater than 155 mg/dL (8.6 mmol/L)
• 3 Hours Post Drink:  Abnormal blood glucose levels: greater than 140 mg/dL (7.8 mmol/L)

If any one of the results is sitting within the abnormal threshold, medical specialists are encouraged to re-test in four weeks and review diet plans. Should two or more of the results appear abnormal, the patient will be diagnosed with gestational diabetes. In this instance, further complications can be treated and managed through careful monitoring of daily blood glucose levels for the remainder of the pregnancy.

Research & Evidence

The 3-hour glucose test is a reputable and common testing tool used in the context of gestational diabetes screening and diagnosis for prenatal patients. Much like the 1 hour glucose tolerance test, this method stems from the work conducted in 1964 by O’sullivan and Mahan. Their findings on the detrimental effects of abnormal carbohydrate metabolism in pregnant women highlighted the dire need for testing, and it has now become a common prenatal practice. 

Regular testing of glucose levels is proven to help in the treatment and management of temporary diabetes in the prenatal stages, and with the global rates of gestational diabetes rising, clear and accessible testing and charting tools are a must. The oral glucose test has been in place for years, yet recent studies are questioning whether or not we can provide better and more accurate results for this growing population of at-risk clients (Bogdanet et al., 2020). Instead of having to rely on a secondary screening test like the 3-hour glucose test development of a single and finite tool would be of great benefit to this medical concern. There are both short-term and long-term detrimental costs for both mother and child should gestational diabetes go undetected so ensuring that testing is viable and trustworthy is a must for the delivery of dignified and well-rounded care. 

A call for a universal standard on the parameters when interpreting blood sugar levels in pregnant patients is made, and work is being done on finding new biomarkers that can also identify gestational diabetes. Results are yet to be validated, and the 1 hour glucose tolerance test, is the precursor to the 3-hour glucose test, yet both of these methods remain favorable and well-used in many healthcare practices (Bogdanet et al., 2020). 

Clinical guidelines and expert recommendations have been established, endorsing its application in many clinical situations. It has evolved into an indispensable component of prenatal healthcare, assisting medical professionals in customizing treatment strategies and determining the need for medical interventions by assessing recent glycemic control.

References

Bogdanet, D., O’Shea, P., Lyons, C., Shafat, A., & Dunne, F. (2020). The Oral Glucose Tolerance Test—Is It Time for a Change?—A Literature Review with an Emphasis on Pregnancy. Journal of Clinical Medicine, 9(11), 3451. https://doi.org/10.3390/jcm9113451

Icahn School of Medicine at Mount Sinai. (n.d.). Glucose screening tests during pregnancy Information | Mount Sinai - New York. Mount Sinai Health System. https://www.mountsinai.org/health-library/tests/glucose-screening-tests-during-pregnancy

Mayo Clinic. (2022, March 24). Glucose tolerance test - Mayo Clinic. Mayoclinic.org. https://www.mayoclinic.org/tests-procedures/glucose-tolerance-test/about/pac-20394296

Mishra, S., Rao, C. R., & Shetty, A. (2016). Trends in the Diagnosis of Gestational Diabetes Mellitus. Scientifica, 2016, 1–7. https://doi.org/10.1155/2016/5489015

O’Sullivan, J. B., & Mahan, C. M. (1964). CRITERIA FOR THE ORAL GLUCOSE TOLERANCE TEST IN PREGNANCY. PubMed, 13, 278–285.