By Cat Troiano
Diabetes is a prevalent chronic metabolic disease, and according to the American Diabetes Association, nearly 10 percent of the American population has this condition. Roughly 1.5 million new cases of diabetes are diagnosed in the United States each year, but 7.2 million American adults who have diabetes are undiagnosed. Understanding which patients should be tested for diabetes and which tests to order can be a proactive step toward reducing the number of undiagnosed cases and saving more lives.
Types and Risk Factors of Diabetes
Diabetes refers to a group of metabolic diseases in which the body is unable to produce or respond to insulin, which is needed for maintaining proper blood glucose levels.
Insulin is a hormone that is produced by beta cells in the pancreas. In a healthy individual, once dietary sugar from carbohydrates is metabolized, insulin is responsible for transporting the glucose from the blood to the body’s muscles and other tissues for use as energy. Any extra glucose gets stored in the liver for a future energy source. In an individual who has diabetes, glucose ends up accumulating in the bloodstream, resulting in hyperglycemia.
Type 1 diabetes, also known as diabetes insipidus, is characterized by the pancreas’ inability to produce insulin. The cause of type 1 diabetes is still unconfirmed, but it is believed to be an autoimmune disorder, and the incurable condition is typically diagnosed early in life. Patients with type 1 diabetes require lifelong treatment with insulin medication.
Type 2 diabetes, also known as diabetes mellitus, is the most prevalent form of diabetes and is characterized by insulin resistance. This means that although the pancreas does produce insulin, the body does not utilize the insulin efficiently to keep blood glucose levels within normal parameters. While type 2 diabetes was once primarily diagnosed in adult patients, the recent trend in rising childhood obesity rates has resulted in an increased rate of diagnosis in children.
Gestational diabetes is a form of diabetes that occurs during pregnancy. It is usually diagnosed in expectant mothers during the third trimester, and once the baby is born, the blood sugar level usually returns to normal.
Prediabetes is the condition that precedes type 2 diabetes in which the blood glucose level is abnormally high, but it is not yet high enough to confirm a diagnosis of diabetes.
According to the Centers for Disease Control and Prevention, one in three Americans has prediabetes. Failure to detect prediabetes and intervene to reverse its course will most likely result in diabetes. Unlike type 1 diabetes, which acts as an autoimmune disorder, type 2 diabetes, which is considered a lifestyle disease, can be prevented. Risk factors for type 2 diabetes include:
• Excess abdominal fat, indicated by a waist circumference measurement that is greater than 100 centimeters in men or greater than 88 centimeters in women
• Triglyceride level that exceeds 150 mg/dL
• HDL cholesterol level that is lower than 40 mg/dL
• Sedentary lifestyle
• Prediabetes, indicated by a fasting glucose level that is greater than 100
• Family history of diabetes
• Previous history of gestational diabetes
• History of giving birth to a baby whose birth weight exceeded nine pounds
• Being 45 years of age or older
• Being of African-American, Native-American, Hispanic-American or Asian-American ethnicity
Patients who possess any of these risk factors must be screened for diabetes to enable early detection before the disease’s damaging complications occur.
Random Blood Glucose Level
For an immediate blood test result in patients who present with symptoms of diabetes, a blood test that does not require fasting can be performed at any time. Symptoms of diabetes include:
• Increased water intake and urinary output
• Unexplained weight loss
• Persistent hunger
• Blurred vision
• Slow healing time for wounds and lacerations
• Frequent infections
A result of 200 mg/dL or higher on a random blood glucose level test is indicative of diabetes.
Fasting Blood Glucose Level
This test reveals a patient’s blood glucose level after fasting overnight. Diabetic patients typically check their own fasting blood glucose level on a daily basis by using a glucometer, which analyzes a drop of blood. Whenever a physician orders a comprehensive metabolic profile, the panel includes the blood glucose level. When patients are directed to fast prior to testing, as is typical when the panel includes a lipid profile, then the blood glucose level result is a fasting level. Fasting blood glucose levels are interpreted as:
Normal Range: 99 mg/dL or lower
Prediabetes Range: 100 to 125 mg/dL
Diabetes Range: 126 mg/dL or higher
When two different tests are performed on two different days and the fasting blood glucose level results on both tests fall within the prediabetic range, then steps must be taken, such as dietary changes and exercise routine implementation, to try to reduce the patient’s risk of his or her prediabetic status advancing to diabetes. There are also additional tests that can be ordered to better assess the patient’s blood glucose level trends.
The hemoglobin A1c (HbA1c) test, for which fasting is not required, is a blood test that reveals a patient’s average blood glucose level for the two to three-month timespan prior to testing. This test evaluates the percentage of glycated, or glucose-coated, hemoglobin in the blood. HbA1c test results are interpreted as:
Normal Range: 5.6 percent or lower
Prediabetic Range: 5.7 to 6.4 percent
Diabetic Range: 6.5 percent or higher
The HbA1c test can be performed to establish a baseline blood glucose level average, and it is also used to monitor diabetic management and progression. The HbA1c test should be ordered annually for patients who have prediabetes. The test may be ordered more often for patients with types 1 or 2 diabetes.
Since the HbA1c test assesses a two to three-month average blood glucose level, pregnancy and certain medical conditions in which the lifespan of a patient’s blood cells is shorter in duration than the typical 120 days, such as hemolytic anemia, can reduce the accuracy of the test.
Like the HbA1c test, the fructosamine test also measures the glycated protein, in this case albumin, in the blood. The two tests differ in that the fructosamine test provides an average blood glucose level for the past two to three weeks instead of the HbA1c test’s result of a two to three-month average. The fructosamine test can be used to provide an earlier assessment of the patient’s glycemic control once dietary and other lifestyle changes are made and insulin therapy has begun.
Normal reference range for fructosamine: 200 to 285 mcmol/L
The higher the fructosamine test result is above 285, the less effective a patient’s current diabetic treatment protocol is in achieving glycemic control.
Oral Glucose Tolerance Test
The glucose tolerance test evaluates blood glucose levels over a two-hour duration, which offers a glimpse into how efficiently a patient’s body processes glucose. After an overnight fast, the first blood sample is drawn for a fasting blood glucose test. The patient is then required to drink a sugary solution, and then an additional blood sample is taken two hours later, for an additional blood glucose level reading. That reading that is taken at the two-hour mark is interpreted as:
Normal Range: 139 mg/dL or lower
Prediabetic Range: 140 to 199 mg/dL
Diabetic Range: 200 mg/dL or higher
The glucose tolerance test is extended to a three-hour duration with a third blood sample drawn when used to screen for gestational diabetes in pregnant women. If at least two of the three sample results are 200 mg/dL or higher, then gestational diabetes is diagnosed.
Ketones in the Urine
When the body does not have a sufficient amount of insulin available to utilize glucose for energy, body fat is burned for energy instead. When this occurs, a byproduct called ketones is produced and expelled from the body through urine. Ketones can be found in the urine and in the blood, and the presence of ketones is known as ketosis. Results for ketones in urine testing are interpreted as follows:
Small: Less than 20 mg/dL
Moderate: 30 to 40 mg/dL
Large: Greater than 80 mg/dL
Having ketones in the urine can be indicative of diabetes. Diabetes is not only cause of ketosis, however. Other causes include anorexia, hyperthyroidism, long durations of vomiting, severe infections, high fevers, excess alcohol consumption and the currently popular ketogenic diet. When a diabetic patient’s ketone levels accumulate to moderate or large numbers and blood glucose levels are also high, the patient is then at risk for a potentially life-threatening condition called diabetic ketoacidosis.
Diabetes is the seventh leading cause of mortality, but with the availability of several different laboratory tests that can be called upon to diagnose and monitor diabetes, patients today have an excellent chance of controlling their condition, enabling them to live a normal life for a full lifespan.