Hair loss disorder	Studies	Findings
Female androgenetic alopecia	Prolactin, FSH, LH, DHEAS	Hyperandrogenism
Telogen effluvium	TSH, other endocrine tests	Metabolic disorder
Alopecia areata, telogen effluvium	ESR, ANA, RF	Autoimmune disease
Alopecia areata	CBC	Pernicious anemia
Tinea capitis	Culture swab, KOH examination, fluorescence with Wood's lamp*	Fungal infection
Telogen effluvium	Hair-pull test with microscopic evaluation	White bulb on shaft
Tinea capitis, environmental/external factor, systemic disease	Same as above	Mid-shaft, fractured hairs
Alopecia areata, alopecia totalis, alopecia universalis	Same as above	Exclamation-point hairs
Telogen effluvium	Hair-pluck test	Increased telogen:anagen ratio
Unclear etiology, mixed signs/ symptoms, failure to improve with treatment	Scalp biopsy	Underlying pathology