Metabolic Syndrome and Laboratory Testing

Metabolic syndrome can be defined as several risk factors that increase the chances that someone will eventually develop a serious condition, like type 2 diabetes, a stroke, or cardiovascular disease (CVD). It should be noted that this is something that is widely accepted in many cases. Still, it is not seen as a definitive diagnosis in some medical circles.

Many risk factors are associated with this condition. If a number of these are present, it is more likely than not the patient in question may have metabolic syndrome. The risk factors that would need to be on the lookout for include:

  • Stored fat in the abdominal area (this is commonly referred to as abdominal obesity)
  • The inability to process glucose effectively and resistance to insulin.
  • Lipid levels in the unhealthy zone; having low good cholesterol levels and increased levels of bad ones.
  • Hypertension (high blood pressure)

Metabolic syndrome is a common condition, and it is known by numerous names, including syndrome X, obesity syndrome, and Reaven syndrome. Many people who have this condition have been told by their medical providers that it is important that they take precautions to avoid any significant health issues in the future. This includes having their blood pressure regularly monitored, getting cholesterol checks frequently, and looking out for signs they may have diabetes. It is important to know that these factors are not linked in any way except for that all of them require a healthier lifestyle to keep things under control.

The National Heart, Lung, and Blood Institute (NHLBI) has estimated that more than 1/3 of the US population is affected. While age is not something that affects the likelihood of suffering from this, those who are overweight, not very active, and/or have excess fat in the abdomen are prone to this.

While many medical organizations worldwide have a set of criteria, they use to describe metabolic syndrome, there are others, like the American Diabetes Foundation, who do not see this as a condition that can be diagnosed. In short, they believe that this is not a clinical condition, per se. Their view is that when the factors are looked at together, they are not anymore useful at predicting CVD or diabetes as they would when they are considered by themselves. The ADA thinks that there needs to be more scientific information available to support this before declaring this an official condition.

While the World Health Organization (WHO) was the first association in the world to define the syndrome in 1998, criteria introduced in 2002 have become the most recognized in the US. This information was included in a report from the National Cholesterol Education Program. This discussed the detection, evaluation, and subsequent treatments for high blood cholesterol in patients who are adults.

In 2005, the NHLBI and the American Heart Association released a report that defined metabolic syndrome and listed a set of criteria that determines if one has the condition. Also, in 2009 the International Diabetes Federation, NHLBI, AHA, World Heart Federation, and the International Association for the Study of Obesity worked together to publish a statement defining the condition. The goal was to offer consistency when researching and providing care to patients. Instead of using obesity to define body status, a combination of waist circumference, population, and country-specific criteria was used.

Criteria for Clinical Diagnosis of Metabolic Syndrome


Criteria for an insulin resistance diagnosis with two other criteria present. Obesity (in relation to waist circumference) and two additional criteria mentioned below.

  • In men, a waist circumference that is 40 inches (102 centimeters, cm).
  • In women, a waist circumference that is 35 inches (88 cm).
  • Body mass index (BMI) BMI >30 kilograms/meter2
  • Triglycerides 150 milligrams/deciliter (mg/dL) 150 milligrams/deciliter (mg/dL) 150 milligrams/deciliter (mg/dL).
  • HDL-C <39 mg/dL in women and <35 mg/dL in men.
  • When taking medications such as statins, <50 mg/dL in women or <40 mg/dL in men is acceptable.
  • Blood pressure 140/90 mm Hg Systolic 130 or diastolic 85 mm Hg. This is the same for those who take medications.
  • Glucose Impaired glucose tolerance, impaired fasting glucose, or type 2 diabetes Fasting >100 mg/dL. The criteria are the same for those on medication.

In cases where metabolic syndrome is present, people tend to have excessive blood clotting and inflammation. There may not be any obvious symptoms but having these features present means a higher likelihood of heart disease, diabetes, stroke, clogged arteries, and death. If complications are not treated, any of the diseases associated with the condition can present themselves within 15 years. Also, smokers who have metabolic syndrome have a less desirable prognosis.

Being inactive and eating an unhealthy diet are considered the root causes of this condition. Also, those who have hypertension and diabetes that is not controlled properly may be diagnosed with metabolic syndrome. PCOS, fatty liver disease, and some cancers seem to be associated with this as well. There are a few cases that may have been linked to genetics.

All the factors that lead to metabolic syndrome are associated in some way. Failing to exercise and being obese can lead to a resistance to insulin. When insulin resistance is present, it affects the production of lipids. This leads to an increase in all the bad cholesterol in the blood and a decrease in the good ones. All of this can lead to plaque deposits on the arteries, which may eventually lead to a stroke and/or CVD. Resistance to insulin can also cause a boost in glucose and insulin in the blood. Too much insulin will increase the amount of sodium retained by the kidneys, which can eventually lead to high blood pressure. If glucose levels are extremely high, they can cause damage to organs and blood vessels.


While a medical professional may have an idea that someone has this condition, it is important to perform tests to confirm this diagnosis. Recommended tests include:


Glucose – In most cases, a fasting glucose is ordered. Still, there are some occasions when a postprandial (after a meal) glucose is performed. Another option is a glucose tolerance test (GTT), which is when numerous tests are taken at scheduled times after a glucose challenge. The goal of this type of test is to determine whether someone already has diabetes or is at an increased risk of eventually being diagnosed with this disease.

Hemoglobin A1c (HbA1c) – This measures the way the body controls glucose and is often used to diagnose diabetes.

Lipid Profile – This keeps track of HDL, LDL, triglycerides, and VLDL. If the triglyceride levels are particularly high, an accurate measurement of the LDL will be ordered.

Some lab tests are not suggested for diagnosing metabolic syndrome. Still, they might be ordered to offer providers more insight. These include:

C-peptide – This indicates the levels of a person’s insulin production.

Urine Albumin – This helps show early signs of kidney disease. WHO recommends this to monitor diabetes.

hs-CRP – This will measure low-level inflammation to assess cardiac risk.

sdLDL – This measures the number of small dense low-density lipoprotein molecules in the body. LDL varies in size, but the denser, smaller ones, which generally form when VLDL is present, or triglycerides are high, may lead to atherosclerosis. While this test is widely available, it is not performed regularly and is not ordered often. The usefulness of this test has not been determined yet.


  • Blood pressure checks to look for signs of hypertension.
  • Waist circumference and weight to keep track of abdominal obesity.
  • BMI, which is a measure of obesity that is widely used by healthcare practitioners everywhere. An adult that has a BMI higher than 30 is considered obese. Keep in mind that this calculation does not pinpoint where the excess weight is located on the body.


Lifestyle modification is the most common treatment for metabolic syndrome. People who have this condition should increase their activity levels and try to lose the excess weight. Smokers are advised to quit.

Benefits of exercise and weight loss include:

  • Lower blood pressure levels
  • Increased sensitivity to insulin
  • Lower LDL and triglyceride levels
  • Higher HDL levels
  • Decrease the risk of stroke or CVD

Drug treatment might be necessary to address the risk factors associated with this condition. Hypertension needs to be treated. Statins may be given to help unhealthy lipid levels. Some medical providers recommend aspirin to decrease the chances of blot clots being present. While some offer medication to boost insulin sensitivity, this is not something that is widely agreed upon.

Additional Details About Metabolic Syndrome

Insulin is a hormone that helps glucose navigate tissue cells. It is then used to produce energy. Insulin will allow the liver to store excess glucose to be used for energy or use it to produce fatty acids. People who have insulin resistance need to have more insulin produced by their pancreas to allow glucose to make its way through all the cells. This can lead to very high glucose and/or insulin concentration in the blood. As time goes on, this can cause problems with some of the vital organs, like the kidneys. It can also cause damage to blood vessels. High insulin levels can lead to the kidneys retaining too much sodium, which can increase blood pressure and eventually lead to hypertension.

The liver uses protein, cholesterol, and triglycerides to make triglyceride-rich very-low-density lipoproteins (VLDL). In the blood, there is an enzyme that removes triglycerides from VLDL to produce intermediate-density lipoproteins (IDL) and then low-density lipoproteins. Keep in mind that LDL is not bad for a while. It is needed for keeping cell walls strong and the production of steroids and sex hormones. However, when LDL has accumulated and oxidized, it can lead to fatty deposits that can become hard and scar the blood vessels. It can also lead to blood clots and CVD.

LDL molecules come in many different sizes. Small dense LDL is more likely to lead to cholesterol deposits in the arteries than their larger counterparts. In obese and/or insulin-resistant people, excessive amounts of VLDL and triglycerides remain in the blood and lead to increases in the number of sdLDL produced.

HDL, or good cholesterol, tend to carry excess cholesterol from the tissues and to the liver. At this time, it is recycled for later use, or it turns into bile. The reverse transport of HDL is the only way to reduce the amount of excess cholesterol in the body. This will help protect the arteries and possibly reverse the build-up of fatty plaque deposits in the arteries. When excessive amounts of VLDL and triglycerides are present, HDL concentrations in the blood are generally lower.