Complete Blood Count (CBC):
White Blood Cell (WBC) Count:
Leukopenia is a common symptom among patients with eating disorders such as anorexia nervosa (binge-purge and restrictive subtypes) and bulimia nervosa (Walsh et al., 2020). This symptom is related to poor nutritional intake. During periods of limited nutritional intake, bone marrow production reduces to conserve energy. It is a dangerous sign as it can increase the risk of infection (Gaudiani, 2015).
Red Blood Cell (RBC) Count:
An estimated one-third of anorexic patients have mild anemia (Hergenroeder, n.d.). Additionally, anemia can be present in patients with bulimia nervosa (Walsh et al., 2020). Decreased nutritional intake poses risks to the production and development of red blood cells from bone marrow. Furthermore, low intake of iron can compound the effects of anemia in patients with eating disorders.
Hemoglobin (HGB):
Hemoglobin levels can be another indicator of anemia. Low dietary intake of iron can lower hemoglobin levels because of low nutritional intake. In anorexia nervosa, low hemoglobin levels can be observed (Hütter et al., 2009).
Hematocrit (HCT):
If hematocrit levels are low, it could indicate nutritional deficiencies. A hematocrit test may be ordered if a patient is experiencing symptoms of anemia, such as shortness of breath, weakness, fatigue, dizziness, and arrhythmia (Walsh et al., 2020). Anemia could indicate abnormal or low nutritional intake.
HbA1C:
BED can worsen glycemic control, and the disorder has a higher prevalence in adults with diabetes than in the general population (Harris et al., 2021). Compared to non-BED “obese” patients, BED “obese” patients had significantly higher HbA1c (Succurro et al., 2015). Furthermore, there is an increased prevalence of eating disorders in adolescents with type 1 diabetes, which can lead to elevated levels of HbA1c. This increases the risk of other complications (Winston, 2020).
Not all people with high levels of HbA1c are overweight. For example, women with PCOS are at higher risk of developing diabetes and HbA1c cannot be used alone in the PCOS population to determine an individual’s risk for developing diabetes (Lerchbaum et al., 2013). Evidence suggests that BED is overrepresented within PCOS populations. In a meta-analysis, women with PCOS were over three times more likely to have abnormal eating disorders scores (based on validated ED screening tools to access abnormal ED scores) as well as being diagnosed with an ED when compared to women without PCOS (Krug et al., 2018).
Additionally, individuals going through puberty have abnormal insulin sensitivity. During mid-puberty, there is a decrease in insulin sensitivity that should recover at puberty completion. Unfortunately, there is evidence that this insulin resistance can remain in youth who are “obese” prior to puberty development (Kelsey & Zeitler, 2016).
Hormone Levels:
Fasting Insulin:
When compared with control group, basal insulin levels were found to be significantly higher in anorexia nervosa subjects (Korek et al., 2012). This can be representative of the breakdown of glucose storage being used due to nutritional deficiencies. Fasting insulin can be important when investigating BED patients. The symptoms of insulin resistance are comparable to an underfed individual: craving carbohydrates, fatigue, mood disruptions, and rarely full. Increasing levels of insulin can be a factor in BED treatment (Enright, 2021). Additionally, women with PCOS are often insulin resistant, increasing their risk of type 2 diabetes and other comorbidities (CDC, 2022).
Cortisol:
Cortisol levels have been observed to be higher in anorexia nervosa patients. The obsession with food may stimulate the hypothalamic-pituitary-adrenal axis, keeping it in a chronically stimulated state (Schorr & Miller, 2017).
Estradiol:
Low estradiol levels are seen in anorexia due to lack of ovarian stimulation from nutritional deficiencies (Warren, 2011). In bulimia nervosa, estradiol levels are also low. Bulimia and anorexia nervosa patients can experience disruptions in their menstrual cycles, which may upset the normal estradiol cycles, indicating it is a consequence rather than a cause (Baker, 2012), putting them at risk for osteoporosis. Increases in individuals binge eating disorder with intact menstrual cycles were observed to have decreased levels of estradiol and increased levels of progesterone (Edler et al., 2007).
Testosterone:
Testosterone levels are observed to be low in male anorexia patients (Skolnick, 2016). Evidence suggests that low testosterone in males is consistent with higher levels of dysregulated eating symptoms, even after controlling for depressive symptoms, body mass index, and age (Culbert et al., 2020). Levels tend to be elevated in females. In women with bulimia, higher testosterone levels may be associated with decreased impulse control during eating and increase purging behaviors (Nicol, 2015). For women with PCOS, they have higher levels of testosterone (Abdelazim, 2020)
DHEA:
Women with PCOS exhibit significantly higher DHEA levels compared to non-PCOS groups (Benjamin et al., 2020).
Leptin:
Leptin is primarily produced by adipose tissue, so levels will correspond with a patient’s fat content. When compared with control group, anorexia nervosa patients had low fasting leptin levels likely related to low weight (Korek et al., 2012). Conversely, in binge eating disorder patients, leptin levels can be high because of the higher adipose tissue reserves. Low leptin levels are consistent with decreased production of estrogen and cease of menstruation (amenorrhea) (Mehler, 2015).
C-Reactive Protein (CRP):
CRP is a test that measures inflammation. High levels of CRP may be a sign of serious infection or other disorder. High levels of CRP are associated with three times more likely to suffer from a heart attack. Individuals with binge eating disorder exhibit higher levels of CRP compared to non-binge eating disorder individuals (Rosário et al., 2022).
Comprehensive Metabolic Panel:
Self-explanatory
Glucose
Total Protein
Albumin
Transthyretin (Prealbumin)
Total Calcium
Sodium
Bicarbonate
BUN
Creatinine
Potassium:
Potassium is crucial in electrochemical gradients for nerve and muscle activity. Low levels of potassium delay repolarization, putting patients at risk for arrhythmias. Individuals with bulimia nervosa are found to have low serum potassium levels (hypokalemia), specifically in patients at lower weights, vomit, and/or abuse laxatives (McCallum, 2023).
Chloride
Purging can cause disruption in serum electrolyte concentrations, particularly chloride levels. In bulimia nervosa patients, vomiting, long-term laxative use, and diuretics decreased chloride levels (Mehler & Rylander, 2014).
Vitals:
Blood Pressure:
Individuals with anorexia nervosa can suffer from hypotension. Symptoms include a low heart rate, difficulty breathing, light-headedness after getting up quickly, arrhythmia (specifically bradycardia). Nutrition deficiencies caused by eating disorders like anorexia nervosa can cause the heart to atrophy and may lead to more serious outcomes (Falconberry, 2022). Repeated purging in bulimia nervosa can cause dehydration, affecting cardiovascular function, contributing to hypotension, postural pulse, and tachycardia. Serum electrolyte changes are related to excessive gastrointestinal and renal losses (McCallum, 2015). Blood pressure should be taken laying down, sitting up, and standing. If the values are greater than 10 value difference, there is likely a problem.
Heart Rate:
Low body weight and malnutrition can lead to bradycardia due to electrolyte disturbances and heart atrophy (Falconberry, 2022; McCallum, 2015). Weight gain can indirectly cause tachycardia due to the increase of body fat.
Temperature:
One sign of malnutrition includes low body temperature. Individuals with chronic undernutrition experience a flattening of normal diurnal temperature curve and experience an eventual onset of hypothermia (Bock, 1993). A low T core below 37 degrees Celsius could indicate a low basal metabolic rate (BMR) and a need for change.
Thyroid Pannel:
Thyroid Stimulating Hormone (TSH):
Normal to below-normal TSH levels are found in anorexia patients (Usdan et al., 2008). There is a positive correlation between caloric intake and TSH values in bulimic patients (Altemus et al, 1996).
Total T3 (overall carbohydrate intake):
Reduced T3 levels are found in anorexia patients due to decreased peripheral conversion (Usdan et al., 2008). Low T3 levels were found in bulimic patients during periods of binging compared to non-bulimic control groups. Additionally, there were significant reductions in T3 compared to the binging period (Altemus et al, 1996). T3 levels usually decrease in proportion to the degree of weight loss (Mehler & Brown, 2014).
T4:
Reduced to normal levels are found in anorexic patients due to decreased peripheral conversion (Usdan et al, 2008). T4 levels are low because T4 is preferentially converted to a biologically inactive reverse T3 (Mehler & Brown, 2014).
Serum Levels:
Self-explanatory
Serum Iron
Serum Magnesium:
Hypomagnesemia is prevalent in patients hospitalized for an eating disorder. The condition is also associated with purging and alkaline urine. Serum magnesium levels should be monitored during refeeding, even after the risk of hypophosphatemia has passed (Raj et al., 2012). Magnesium is an important factor in metabolism and can be seen with refeeding syndrome. Symptoms include nausea and vomiting, tremors, seizures, and muscle spasms (Refeeding Syndrome, 2022).
Serum Phosphorus:
Serum phosphate deficiency is common in eating disorder patients that lose body weight. It is the most common feature of refeeding syndrome, causing muscle weakness, trouble breathing, seizures and more (Refeeding Syndrome, 2022).
Thiamine (vitamin B1)
Low thiamin levels have been observed in patients with eating disorders that lose body weight. Thiamine deficiency can be triggered by refeeding with carbohydrates, resulting in severe neurological symptoms including ataxia, amnesia, and delirium (Refeeding Syndrome, 2022).
Amylase/Lipase
Folate
Vitamin B-12
Vitamin D
Ferritin
Transferrin
Creatine Kinase
High levels of creatine kinase have been observed in an individual with anorexia nervosa (Walder & Baumann, 2008, Winston, 2012). Underweight individuals can experience elevated symptoms of CK due to breakdown of muscle mass for energy. Additionally, over exercising can show an increased serum CK.
Liver Panel:
Alkaline Phosphatase:
One study found alkaline phosphatase levels to be within normal range for all participants, including patients with anorexia, bulimia nervosa, and EDNOS (Modan-Moses et al., 2015). However, it is important to monitor levels as they can increase due to refeeding syndrome. These levels can revert to normal levels upon reduction of the rate of refeeding (Vootla, 2015).
ALT/SGPT
Elevated alanine aminotransferase levels are frequently reported in patients with AN and overweight subjects or who have hyperlipidemia, which can be found associated with BED and BN. Body mass index was found to be inversely associated with ALT, indicating that elevated levels can be seen with chronic malnutrition and low levels with high BMI (Lelli et al., 2014).
AST/SGOT
Elevated aspartate aminotransferase levels are frequently reported in patients with AN and overweight subjects or who have hyperlipidemia, which can be found associated with BED and BN. Body mass index was found to be inversely associated with AST, indicating that elevated levels can be seen with chronic malnutrition and low levels with high BMI (Lelli et al., 2014).
Lipid Profile:
Total Cholesterol (TC):
Hypercholesterolemia is found in patients with anorexia nervosa (Nestel, 1974; Jáuregui-Garrido et al., 2012; Nivedita et al., 2015). Weight restoration tends to decrease TC/HDL and LDL/HDL ratios (Jáuregui-Garrido et al., 2012). Compared with non-bulimic women, bulimic patients had significantly enhanced serum levels of cholesterol and triglycerides (Monteleone et al., 2005). Sex hormones are primarily synthesized from cholesterol. Low serum cholesterol levels can cause disruptions in sex hormone production and other nutrients such as vitamin D and bile acids (Craig et al., 2022).
High Density Lipoproteins (HDL):
BED patients exhibit significantly lower high-density lipoprotein cholesterol levels (Succurro et al., 2015). Higher concentration of HDL has been found in anorexia nervosa patients (Jáuregui-Garrido et al., 2012).
Low Density Lipoproteins (LDL):
One study suggests that there is an existence of LDL cholesterol risk in all groups of eating disorders (AN-R, BN, BED) (Nakai et al., 2016).
Triglycerides (TG):
Compared with non-bulimic women, bulimic patients had significantly enhanced serum levels of cholesterol and triglycerides (Monteleone et al., 2005). Unsure what informing fat intake means from text.
General note: “The higher lipoprotein levels in patients with anorexia nervosa could be explained by a higher rate of synthesis of cholesterol-rich lipoprotein in these patients… Another explanation for these findings may be the existence of a low catabolism of cholesterol-rich lipoprotein” (Jáuregui-Garrido et al., 2012).
Tests:
Electrocardiogram (EKG):
For individuals with eating disorders that cause extreme weight loss, cardiovascular events are one of the main causes of sudden death. Patients with anorexia and bulimia nervosa can experience bradycardia, long QT intervals and QT dispersion (Takimoto et al., 2004). Additionally, prevalence of early repolarization pattern in anorexia nervosa patients has been seen in studies (Frederiksen et al., 2021). Research is limited in binge-eating disorder patients.
DEXA:
DEXA scans are important in determining the severity of a restrictive eating disorder. Bone mass density was found to be significantly lower than healthy controls in both anorexia and bulimia nervosa patients (Robinson et al., 2016). It can also be used to determine body fat index. Research is limited to binge eating disorder patients. Additionally, those with amenorrhea can require a DEXA scan because of the well-known effects of estrogen on bone. A lack of menstruation can signify potential bone damage (Indirli et al., 2021).
