Table 3

Eating disorder laboratory evaluation and diagnostic testing50–52

Lab/test	When to use
Basic blood chemistry: serum electrolytes; renal function (BUN, Cr); calcium; liver function tests; thyroid stimulating hormone (TSH); complete blood count (CBC), differential and platelets; urinalysis	All patients with suspected eating disorders
Additional blood chemistry: iron studies; vitamin D; vitamin B12; magnesium; phosphorous	Malnourished and severely symptomatic patients
Additional blood chemistry: serum luteinizing hormone; follicle stimulating hormone; prolactin; estradiol; thyroid stimulating hormone (TSH)—if not previously obtained; urine pregnancy test	▸ Patients with delayed menarche—no menses by age 15 ▸ Absence/delay of secondary sexual characteristics by age 13; ▸ Secondary amenorrhea (no menses for three consecutive months)
Toxicology screen	Patients with suspected substance use
Radiological imaging: dual energy X-ray absorptiometry (DXA), radiographs, advanced imaging	▸ DXA for patients with amenorrhoea for 6 months or more of prolonged oligomenorrhoea (<6 periods in 24 months); ▸ Radiographs to evaluate for stress fractures, or more advanced imaging if needed
ECG	▸ Patients with syncope, recurrent near syncope, palpitations, resting supine heart rate <50 bpm ▸ Rapid weight loss; weight <80% of ideal body weight ▸ Hypophophatemia

All patients with suspected or confirmed eating disorders should undergo laboratory testing as indicated. Additional testing should be performed based on presenting signs and symptoms. Reprinted with permission from Intermountain Healthcare.