Lab Testing Helps in Diagnosing Prediabetes

 When you have glucose levels that are above normal, but not as high as to be diagnosed as a diabetic, you are probably suffering from prediabetes, also called impaired glucose tolerance or impaired fasting glucose. Data released by the Centers for Disease Control and Prevention recently have indicated that in the U.S. alone, during the year 2012, 86 million adults were suffering from prediabetes. Normally, people who have prediabetes do not exhibit any symptoms, but if no action is taken to reduce their glucose levels, they increasingly risk developing diabetes within the next decade of their lives. 

The United States Preventive Services Task Force, as well as the American Diabetes Association (ADA), recommends that all adults who are 45 years or more be screened for diabetes, as well as those overweight adults who are below 45 years, and have additional risk factors that could lead to type 2 diabetes. 

These risk factors are: 

  • Those who are physically inactive, obese and overweight 
  • Those who have a first-degree close relative that suffers from diabetes 
  • Women who have delivered children of more than 9 pounds weight and earlier suffered from gestational diabetes 
  • Women with PCOS (polycystic ovary syndrome) 
  • Those of a race or ethnicity that is considered high-risk, like Pacific Islanders, Asian Americans, Native Americans, Latino, or African Americans. 
  • People who have hypertension or high blood pressure and are taking medications for it 
  • Patients with less than 35 mg/dL or 0.90 mmol/L HDL cholesterol, and/or those with a high triglyceride level which is more than 2.82 mmol/L or 250 mg/dL 
  • If you have an A1C level above or equal to 5.7 or have been identified as prediabetic by any previous screenings 

Signs and Symptoms 

At the time of diagnosis, those with prediabetes may not exhibit any definite signs or symptoms of diabetes. 

Laboratory Tests 

The objective of any testing for diabetes is to screen patients with hyperglycemia or high blood glucose levels so that diabetes or prediabetes can be detected and diagnosed. Testing also helps in monitoring and controlling the levels of glucose over a period of time and can help in detecting and monitoring any complications. 

Tests can be used: 

  • When a person exhibits signs and symptoms that indicate diabetes 
  • When a person has other risk factors or conditions that are normally associated with diabetes 
  • When persons with an acute condition report to emergency rooms 
  • Regular testing for glucose control and monitoring diabetes 

Diabetes can occur during pregnancy, and screening for gestational diabetes at this time is different from the testing adopted for the general population. More information available in the section on Gestational Diabetes 

The American Diabetes Association suggests several different tests to screen and diagnose diabetes or prediabetes, and every one of these tests has its limitations, advantages, and disadvantages. If abnormal results are obtained from any of the tests listed below, then the tests are carried out again another day. For confirming a diagnosis of diabetes, the repeated result must show the same degree of abnormality.

Tests include: 

Fasting Glucose Level:

Indications:  

  • 70 to 99 mg/dL (3.9 to 5.5 mmol/L) indicates normal fasting glucose 
  • 100 to 125 mg/dL (5.6 to 6.9 mmol/L) indicates prediabetes or impaired fasting glucose 
  • Equal to and above 126 mg/dL (7.0 mmol/L) a result, repeated more than once indicates diabetes 

A1c test, also called glycohemoglobin or hemoglobin A1c, is a test that indicates the average amount of glucose for the previous 2 to 3 months. For this test, there is no need for patients to fast for 8 hours, or have multiple blood samples taken, but it is not a test that is meant for everyone. It should not be used for diagnosing diabetes in women who are pregnant, those who have recently suffered heavy bleeding or received blood transfusions, people with chronic diseases of the liver or kidney, people with blood disorders like anemia for iron deficiency, vitamin B12, and other hemoglobin variants. A1c tests should be used for screening or diagnosis if they have been standardized to acceptable laboratory standards. In the present day, point-of-care tests that are used in doctor’s offices or at the bedside of a patient vary a lot and are not useful for diagnosis, though they can be used for monitoring treatment, lifestyles, and drug therapies. 

A1c level Indications:

  • 5.7% (39 mmol/mol) or less is considered normal 
  • 5.7% to 6.4% (39-46 mmol/mol) indicates prediabetes 
  • 6.5% (47 mmol/mol) or higher indicates diabetes 

OGTT is a 2-hour test for glucose tolerance. In this test, blood is drawn after fasting and followed by the patient drinking a 75-gram glucose drink. A blood sample is again drawn two hours after the glucose is consumed. 

Glucose Level 2 hours after the 75-gram drink Indication  

  • 140 mg/dL (7.8 mmol/L) or less indicates normal glucose tolerance 
  • 140 to 199 mg/dL (7.8 to 11.1 mmol/L) indicates impaired glucose tolerance or prediabetes 
  • 200 mg/dL (11.1 mmol/L) or more results, when tested more than once, indicates diabetes 

Blood samples are sometimes drawn for measuring glucose even when the person has not been fasting, often for a CMP or comprehensive metabolic panel. Results here that are 200 mg/dL (11.1 mmol/L) or higher are an indication of diabetes. Abnormal results must always be followed up with an additional test.  

Besides these diabetes tests that have been detailed above, there can also be other tests used to screen, diagnose, monitor, and evaluate for type 2 diabetes. 

Diabetes autoantibodies – this test helps in distinguishing between the two types of diabetes, Type 1 and Type 2, when the diagnosis is otherwise not clear. When one or more antibodies are detected, this confirms Type 1 diabetes. 

Insulin, C peptide – this test monitors the production of insulin. 

Lab Testing Helps in Diagnosing Prediabetes 

When you have glucose levels that are above normal, but not as high as to be diagnosed as a diabetic, you are probably suffering from prediabetes, also called impaired glucose tolerance or impaired fasting glucose. Data released by the Centers for Disease Control and Prevention recently have indicated that in the U.S. alone, during the year 2012, 86 million adults were suffering from prediabetes. Normally, people who have prediabetes do not exhibit any symptoms, but if no action is taken to reduce their glucose levels, they increasingly risk developing diabetes within the next decade of their lives. 

The United States Preventive Services Task Force, as well as the American Diabetes Association (ADA), recommends that all adults who are 45 years or more be screened for diabetes, as well as those overweight adults who are below 45 years, and have additional risk factors that could lead to type 2 diabetes. 

These risk factors are: 

Those who are physically inactive, obese and overweight 

Those who have a first-degree close relative that suffers from diabetes 

Women who have delivered children of more than 9 pounds weight and earlier suffered from gestational diabetes 

Women with PCOS (polycystic ovary syndrome) 

Those of a race or ethnicity that is considered high-risk, like Pacific Islanders, Asian Americans, Native Americans, Latino, or African Americans. 

People who have hypertension or high blood pressure and are taking medications for it 

Patients with less than 35 mg/dL or 0.90 mmol/L HDL cholesterol, and/or those with a high triglyceride level which is more than 2.82 mmol/L or 250 mg/dL 

If you have an A1C level above or equal to 5.7 or have been identified as prediabetic by any previous screenings 

Signs and Symptoms 

At the time of diagnosis, those with prediabetes may not exhibit any definite signs or symptoms of diabetes. 

Laboratory Tests 

The objective of any testing for diabetes is to screen patients with hyperglycemia or high blood glucose levels so that diabetes or prediabetes can be detected and diagnosed. Testing also helps in monitoring and controlling the levels of glucose over a period of time and can help in detecting and monitoring any complications. 

Tests can be used: 

  • When a person exhibits signs and symptoms that indicate diabetes 
  • When a person has other risk factors or conditions that are normally associated with diabetes 
  • When persons with an acute condition report to emergency rooms

Diabetes can occur during pregnancy, and screening for gestational diabetes at this time is different from the testing adopted for the general population. More information available in the section on Gestational Diabetes 

The American Diabetes Association suggests several different tests to screen and diagnose diabetes or prediabetes, and every one of these tests has its limitations, advantages, and disadvantages. If abnormal results are obtained from any of the tests listed below, then the tests are carried out again another day. For confirming a diagnosis of diabetes, the repeated result must show the same degree of abnormality. Tests include: 

Fasting Glucose Level: Indications:  

  • 70 to 99 mg/dL (3.9 to 5.5 mmol/L) indicates normal fasting glucose 
  • 100 to 125 mg/dL (5.6 to 6.9 mmol/L) indicates prediabetes or impaired fasting glucose 
  • Equal to and above 126 mg/dL (7.0 mmol/L) a result, repeated more than once indicates diabetes 

A1c test, also called glycohemoglobin or hemoglobin A1c, is a test that indicates the average amount of glucose for the previous 2 to 3 months. For this test, there is no need for patients to fast for 8 hours, or have multiple blood samples taken, but it is not a test that is meant for everyone. It should not be used for diagnosing diabetes in women who are pregnant, those who have recently suffered heavy bleeding or received blood transfusions, people with chronic diseases of the liver or kidney, people with blood disorders like anemia for iron deficiency, vitamin B12, and other hemoglobin variants. A1c tests should be used for screening or diagnosis if they have been standardized to acceptable laboratory standards. In the present day, point-of-care tests that are used in doctor’s offices or at the bedside of a patient vary a lot and are not useful for diagnosis, though they can be used for monitoring treatment, lifestyles, and drug therapies. 

A1c level Indications 

  • 5.7% (39 mmol/mol) or less is considered normal 
  • 5.7% to 6.4% (39-46 mmol/mol) indicates prediabetes 
  • 6.5% (47 mmol/mol) or higher indicates diabetes 

OGTT is a 2-hour test for glucose tolerance. In this test, blood is drawn after fasting and followed by the patient drinking a 75-gram glucose drink. A blood sample is again drawn two hours after the glucose is consumed. 

Glucose Level 2 hours after the 75-gram drink Indication  

  • 140 mg/dL (7.8 mmol/L) or less indicates normal glucose tolerance 
  • 140 to 199 mg/dL (7.8 to 11.1 mmol/L) indicates impaired glucose tolerance or prediabetes 
  • 200 mg/dL (11.1 mmol/L) or more results, when tested more than once, indicates diabetes 

Blood samples are sometimes drawn for measuring glucose even when the person has not been fasting, often for a CMP or comprehensive metabolic panel. Results here that are 200 mg/dL (11.1 mmol/L) or higher are an indication of diabetes. Abnormal results must always be followed up with an additional test.  

Besides these diabetes tests that have been detailed above, there can also be other tests used to screen, diagnose, monitor, and evaluate for type 2 diabetes. 

Diabetes autoantibodies – this test helps in distinguishing between the two types of diabetes, Type 1 and Type 2, when the diagnosis is otherwise not clear. When one or more antibodies are detected, this confirms Type 1 diabetes. 

Insulin, C peptide – this test monitors the production of insulin. 

Urine and/or Blood Ketone Tests are often ordered for those patients who come to emergency rooms with indications of acute hyperglycemia, to those who need monitoring because they are being treated for ketoacidosis. Ketone buildup occurs when the effectiveness of the insulin or its amount decreases in the body.