If you experience symptoms like significant weight loss, an obsessive focus on body image, extreme dietary restrictions, psychological stress, or an intense fear of gaining weight, it is important to consult with a psychiatrist or nutritionist. Early detection and intervention are crucial in reducing the risks associated with anorexia nervosa.

Depending on the severity and duration of the condition, your doctor may perform physical exams and review your medical history to rule out other similar health conditions. If the symptoms are unclear, your physician may recommend various tests to aid in the diagnosis.

Physical Examination

During a physical exam for anorexia nervosa, the following aspects are typically assessed:

Examination of physical signs like dry skin, sunken eyes, and the development of soft hair over the body.
Calculation of your body mass index (BMI), which is less than 17.5 in adults or less than 85% of the expected weight for children.
Evaluation of vital signs, including heart rate, blood pressure, body temperature, and other malnutrition indicators.
Abdominal examination for stretch marks and palpation of the liver.

Psychological Evaluation

A psychological evaluation for anorexia may involve:

Analysis of behavior patterns such as substance abuse, self-harm, or suicidal tendencies.
Review of your family or medical history for any other psychological disorders.
Evaluation of your views on eating, appearance, and exercise.

DSM-5 Guidelines

Anorexia nervosa is classified under Feeding and Eating Disorders in the latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The DSM-5 does not have a specific BMI cutoff for diagnosing anorexia nervosa.

The diagnostic criteria for anorexia nervosa include the following (all of which must be met for a diagnosis):

Restriction of energy intake relative to requirements, leading to significantly low body weight. (Criterion A)
Intense fear of gaining weight or persistent behaviors that interfere with weight gain. (Criterion B)
Distorted perception of one's body weight or shape or failure to recognize the risks of low body weight. (Criterion C)

The DSM-5, in its 2013 revision, removed the requirement for amenorrhea (absence of periods) as a diagnostic criterion, as it did not apply to males, women before or after menstruation, or those using birth control, and some women with anorexia still experience menstrual activity.

Levels of Severity

The DSM-5 uses BMI as an indicator of the severity of anorexia nervosa:

Mild: BMI greater than 17
Moderate: BMI between 16–16.99
Severe: BMI between 15–15.99
Extreme: BMI less than 15

Laboratory Tests

While there is no specific test to definitively diagnose anorexia, lab work can help uncover any underlying health issues linked to the condition. Common lab tests used in the diagnosis include:

Blood Sugar Test: Individuals with type 1 diabetes are at an increased risk of anorexia.
Electrolyte Level Test: Used to assess the severity and health effects of anorexia.
Complete Blood Count (CBC): This can help identify underlying conditions that could be contributing to anorexia.
Comprehensive Metabolic Profile (CMP): This test evaluates 14 parameters in the blood, providing insights into the body’s chemical balance and metabolism.
Urinalysis: A routine urine test can help diagnose underlying conditions related to anorexia, as well as hydration and fluid intake levels.
Electrocardiogram (ECG): Used to assess heart function and detect any related abnormalities.
Liver Function Test: These tests evaluate liver health and can be used to assess malnutrition and protein deficiencies.
Luteinizing Hormone (LH) Response to Gonadotropin-Releasing Hormone (GnRH): This test evaluates the pituitary gland’s response to GnRH and can help detect hypogonadism, which is commonly seen in anorexia nervosa cases.