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The Eating Disorder Medical Test and Nutrition Lab Guide

Do you ever wonder which tests or labs you should have checked if you are diagnosed with an eating disorder? Or what the results even mean? Clients are often asking themselves, “Am I sick enough for treatment? Can’t I just keep on going like I have been? I feel fine.” Looking at vital signs and labs can often be a wake up call to show an individual that indeed, they are not fine. 

Additionally, it is important to note that the body has brilliant mechanisms and storage systems for keeping vital signs and lab values within normal limits. This is one of the reasons why some bodies can go months, even years, with inadequate nutrition. As you get your labs assessed, having most, or even all, within normal range does NOT mean that your body is “fine.” It simply means that your reserves are still able to meet your needs, but eventually, that too will give out. Starting treatment sooner rather than later will decrease the medical complications you may have to face should you continue in your behaviors. 

Lastly, a patient does not need to be “underweight,” “super skinny,” or “anorexic” to be malnourished. Rapid weight loss, chronic dieting, the long-term suppression of one’s natural body weight, and purging can result in lab abnormalities regardless of the patient’s size or weight. 

If you have been diagnosed with any form of an eating disorder, ask your primary care provider to order the following labs.  Use the following information to interpret the labs to better understand how it is tied to nutrition and eating disorder behaviors. 

Vitals Signs

Vital signs refer to the tests used to measure the body’s respiratory system.  Abnormal vital signs indicate a problem with the health and functionality of the body’s ability to maintain the proper oxygen and carbon dioxide levels. The four main vital signs are respiration rate, blood pressure, body temperature and pulse rate. 

  • Blood pressure: blood pressure is a measurement of the pressure in the veins exerted by the heart to move blood throughout the body. Blood pressure can be low if you do not eat or drink enough and become dehydrated or malnourished. In this state, blood pressure can also drop too low between sitting and standing up, which can cause dizziness, lightheadedness or fainting. The best way to help get blood pressure back into a normal range is rehydration and nourishment. A blood pressure of less than 90 mm Hg for systolic, and less than 60 mm Hg diastolic is considered low. 
  • Temperature: when the body does not have enough fat to keep itself insulated or warm, it can become cold, or hypothermic. This happens if you do not eat enough food to stay adequately nourished. Signs of hypothermia are feeling cold all the time, always needing multiple layers of clothing, or developing a layer of soft, fine hair called “lanugo.” This hair helps keep the body warm when it does not have enough fat. Hypothermia is defined as a body temperature of less than 95 °F.
  • EKG: An EKG (or ECG) stands for electrocardiogram which is a type of test that measures the electrical signals and rhythm of your heart. It records the timing and strength of your heart beats. This test is important for people who have eating disorders because eating habits affect heart rate and strength. The heart is a muscle, so if you do not eat enough food to help keep your muscles strong, they weaken. As the heart weakens and the body tries to conserve energy, it will beat less often. This can lead to abnormal heart rhythms or a low heart rate. An EKG can detect these abnormal rhythms or slow heart rate. Low heart rate (or bradycardia) is defined as a heart beat less than 60 beats per minute. Low heart rate can resolve with proper nutrition. 

It should be noted that there is a difference between low heart rate in an athlete and low heart rate in someone with an eating disorder. An athlete’s heart rate will be low because there is increased muscle mass in the heart, allowing it to beat less frequently. A low heart rate in the setting of an eating disorder is actually indicative of the opposite- a weak heart. This is the body’s way of conserving energy in the setting of poor nutrition. This can result in feeling easily winded, dizzy, or tired during day-to-day activities. This does not happen in athletes. The best way to improve heart function and heart rate is proper nutrition.

Metabolic/Electrolyte Labs

A complete metabolic panel is important in order to check on your metabolism, or how your body is using energy in order to function properly. The results are indicators of electrolyte balance, the health of your kidneys and liver, acid-base balance, as well as your sugar and protein levels. The following lab results are frequently monitored in the setting of eating disorders. Below is a detailed list of key metabolic labs and how to interpret them in light of an eating disorder.

  • Glucose: glucose is another name for the amount of sugar in your blood. The body uses glucose as its main energy source in order to keep the body working properly. Blood sugar can drop too low if you are not eating enough or are malnourished. Because the brain relies on glucose as its main energy source, one of the symptoms of low blood sugar is confusion. It can also lead to dizziness, seizures, or loss of consciousness. Low blood glucose is defined as <70 mg/dL.
  • Albumin: Albumin is a protein in the blood. This lab is frequently drawn to assess protein status. Albumin has a half life of 2 weeks, which means that it is not a good indicator of recent protein intakes. Albumin levels can decrease in the setting of infection, trauma, liver disease, renal disease, and it can increase in the setting of dehydration. Low albumin levels can be seen in the setting of an eating disorder due to chronic low protein intakes or malnutrition. A normal albumin level is 3.4 to 5.4 g/dl for adults. 
  • Prealbumin: Prealbumin is another protein in the blood. It has a shorter half life than albumin (only 2-3 days), therefore it gives a better idea of more recent protein intakes and protein loss. It can be low during times of stress, infection, liver disease or trauma. Low prealbumin levels can be seen in the setting of an eating disorder due to low protein intakes, lack of adequate zinc in the diet, or malnutrition. High levels can indicate iron deficiency. A normal prealbumin level is 15-36 mg/dl for adults. 
  • BUN: Blood urea nitrogen is a test used to determine kidney function. Low levels can be indicative of dehydration. High levels can be indicative of malnutrition or overhydration. Some people with eating disorders will overhydrate (drink lots of water) in order to make his/her weight look higher (AKA “fluid loading”). A normal BUN levels is 10-20 mg/dl for adults and 5-18 mg/dl for children. 
  • Creatinine: creatinine is a waste product produced when the body breaks down muscle tissue. The kidneys are responsible for removing this waste product. High creatinine levels can occur if your kidneys are not working properly, if you are dehydrated, participating in rigorous exercise, or if you eat a large amount of protein. Malnutrition, extreme weight loss and low muscle mass can cause creatinine levels to be low. Normal creatinine levels depend on age and gender. 
  • Calcium: calcium is an important mineral and electrolyte in the blood. It helps with structure/strength of the bones and teeth. Serum calcium is low with the long term use of diuretics or purging. This can ultimately affect heart rhythms and bone calcification (which leads to osteoporosis). An acceptable calcium range is 9-10.5 mg/dL. 
  • Ionized calcium: ionized calcium is different from serum calcium. It is a better indicator of calcium status (amount of calcium stored in the body) than serum calcium. Elevated ionized calcium can be due to taking too much vitamin D, and low levels can be caused by lack of adequate amounts of calcium or vitamin D, malabsorption, or malnutrition. An acceptable ionized calcium range is 4.4-5.4 mg/dL.
  • Sodium: sodium is an important mineral and electrolyte in the blood. Sodium can be high or low in eating disorder patients depending on the situation. If you are dehydrated or malnourished, your sodium can be high. If you are water loading to make your weight look higher, your sodium can be low. Sodium can also be low if you are using diuretics. An acceptable sodium range is 135-145 mEq/L.
  • Phosphorous: phosphorous is an important mineral or electrolyte in the body. It can drop early in the treatment of an eating disorder. This phenomenon is called “refeeding syndrome.” Refeeding syndrome is defined as electrolyte imbalances seen during reintroduction of nutrition after a period of starvation. Due to fluid shifts, phosphorus can drop dangerously low. Low phosphorus levels result in abnormal heart rhythms. Your treatment team will keep a very close eye on this mineral during the refeeding process.  An acceptable serum phosphorus level is 2.4-4.1 mg/dL.
  • Potassium: potassium can be high or low in eating disorder patients depending on the situation. Potassium will be high if you are dehydrated, malnourished, if you are using diuretics or are purging. Low potassium can occur in the setting of refeeding syndrome. If potassium is too low, this can lead to cardiac arrest. An acceptable potassium range is 3.5-5 mEq/L.
  • Magnesium: magnesium can be low in the setting of laxative use, purging, or during refeeding syndrome. An acceptable magnesium range is 1.7-2.2 mg/dL.
  • Chloride: chloride can be high or low in eating disorder patients depending on the situation. If you are severely dehydrated, your chloride can be high. If you are water loading to make your weight look higher, purging, or malnourished, your chloride can be low. An acceptable chloride range is 98-108 mmol/L.

Anemia Profile/Vitamins and Minerals

The body needs a variety of vitamins, minerals, and trace elements in order to facilitate proper growth, development, function, and prevent long term complications and disease. The following lab tests are commonly assessed in the setting of an eating disorder. 

  • Hemoglobin: hemoglobin is a protein in the red blood cells. It is responsible for carrying oxygen throughout the body. If your body does not have the right amounts of vitamins and minerals it needs to function, it will not produce enough red blood cells. The result is anemia and low hemoglobin levels. Normal hemoglobin levels are based on age and gender. 
  • Hematocrit:hematocrit is the proportion of blood that contains red blood cells. It is usually expressed as a percentage. Low hematocrit levels can be caused by inadequate intakes of certain vitamins/minerals such as iron, vitamin B12, or folate. It can also occur in the setting of restriction, malnutrition, or overhydration. High levels can be caused by dehydration. Normal hematocrit levels are based on age and gender. 
  • Serum iron: serum iron is the amount of iron in your serum (liquid left over when red blood cells and clotting factors are removed). Serum iron levels can be high if you have consumed too much iron, and it can be low if you have not eaten enough iron. Low serum iron is usually present if someone with an eating disorder is not eating enough iron-rich foods. Iron is important in the body because it helps carry oxygen from the lungs to the rest of the body. Without enough iron in the diet, you may feel fatigued, weak, short of breath, or lightheaded. Sources of iron include spinach, red meat, legumes, shellfish, chicken, turkey, fish, beans, and iron-enriched grains. A normal serum iron range is 60-170 mcg/dL.
  • Serum ferritin: serum ferritin is a measurement of the amount of iron you have stored in your body. Ferritin is a protein that stores iron. Serum ferritin levels can be high if you have consumed too much iron, and it can be low if you have not eaten enough iron. Low serum ferritin is usually present if someone with an eating disorder is not eating enough iron-rich foods. A normal serum ferritin range is 20-500 ng/ml in men and 20-200 ng/dl in women. 
  • Zinc: zinc is an important mineral that helps with many bodily functions, such as supporting the immune system, as well as growth and wound healing. A serum zinc level could be low in the setting of restriction or not eating enough foods that are rich in zinc. Sources of zinc include eggs, whole grains, potatoes, meat, shellfish, legumes, dairy, nuts and seeds. A normal serum zinc range is 0.60-1.20 mcg/mL for age 0-10 years, and 0.66-1.10 mcg/mL for 11 years and older. 
  • Vitamin B12: B12 is an important vitamin that the body uses to help maintain nerve function, make DNA, and helps with the production of blood cells. Low levels are usually caused by inadequate intake of foods that contain vitamin B12 or malnutrition. Those at highest risk for deficiency are vegetarians and vegans. Low vitamin B12 levels can result in permanent nerve damage. Good sources of vitamin B12 include clams, liver, fish, crab, beef, fortified grains, tofu, milk, cheese, eggs. A normal serum vitamin B12 range is 200-900 ng/dl.
  • Folate: folate is a B vitamin that is essential for cell growth, making red blood cells, and producing DNA. Low folate levels are caused by inadequate intake of foods that contain  folate or malnutrition. It can also be low in the setting of B12 deficiency. Those at highest risk for deficiency are vegetarians and vegans. Foods high in folate include legumes, eggs, asparagus, broccoli, avocado, leafy greens, citrus fruits, corn, nuts and seeds, fortified grains. A normal serum folate range is 2.5-10 ng/ml.
  • Vitamin D, 25-hydroxy: vitamin D is essential in helping the body absorb calcium and maintain bone health. It can be found in a variety of foods including fish, milk, yogurt, egg yolks, cheese. Vitamin D is also produced when your skin is exposed to the sun. Low vitamin D levels are usually caused by lack of vitamin D in the diet, especially in the setting of severe restrictions, as well as lack of sun exposure. Vitamin D is a fat soluble vitamin, which means you need to eat fat to absorb it. If your diet is low in fat, you can also be at risk for vitamin D deficiency. A normal 25-hydroxy vitamin D level is greater than 30 ng/ml.  


A lipid panel measures the different amounts of types of fats in our blood. Fats are necessary for the body to function correctly, but a balance must be achieved in order to maintain health. Alterations in lipid levels can occur in the setting of eating disorders. The following tests are all included in a lipid panel. 

  • Total cholesterol: this is a type of fat in your blood. It is necessary to form cell membranes, make hormones, and it can help make substances needed to absorb nutrients. Too much cholesterol in the blood can be caused by genetics or diet, and usually increases risk of cardiovascular disease. In eating disorders, it is not uncommon to have high cholesterol levels. This is due to the liver’s inability to work properly or the body’s inability to regulate hormones due to malnutrition. “High” cholesterol is defined as total cholesterol >200 mg/dl. High cholesterol in the setting of an eating disorder will normalize with weight restoration; there is no need to follow a low fat diet if high cholesterol is due to an eating disorder. 
  • HDL cholesterol: this is the type of cholesterol that decreases risk for heart disease. A desirable value is greater than 40 mg/dl for women, greater than 50 mg/dl for men, and greater than 45 mg/dl in children. 
  • LDL cholesterol: this is the type of cholesterol that increases risk for heart disease. A desirable value is less than 130 mg/dl.
  • Triglycerides: this is another type of fat in the blood. The body uses this type of fat as an energy source. High levels have been linked to an increased risk for heart disease. A desirable values is less than 100 mg/dl in ages 0-9, less than 130 mg/dl in ages 10-19, and less than 150 mg/dl in adults. 

Urine analysis

  • Specific gravity: specific gravity is determined using a urine sample. This test compares the density of urine to the density of water. This can be an indicator of kidney function, but also dehydration or overhydration. If this level is high, it can be a sign of dehydration. If the level is low, then this could be a sign of overhydration. This might be the case if a patient tries to drink lots of water before an appointment to make it look like he/she gained weight. An acceptable range for specific gravity is 1.002 and 1.030.

Bone Density

  • DEXA: bone density, or how strong your bones are, is measured using a test called a DEXA scan (dual energy x-ray absorptiometry). This test can reveal signs of osteoporosis or the likelihood of fracturing a bone. In the case of eating disorders, it is important to monitor bone health. Malnutrition can cause menses to stop in females, which affects hormone levels. This change in hormones can cause a decrease in bone production/mineralization, which puts you at higher risk for breaking bones. The only way to correct this is treatment for the eating disorder, weight restoration, and calcium and vitamin D supplementation. 

There are many different tests that can be ordered to assess health in someone who has an eating disorder. This list is a good place to start. Your medical team may order more assessments depending on the type of eating disorder presented. It should be noted that lab value ranges can vary depending on the lab running the test and equipment used. Always refer to the range provided on your lab results. Lastly, speak with your doctor and treatment team regarding the interpretation of the test results and how best to proceed to the type of treatment you need. 


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