Laboratory Studies
There are no specific laboratory studies available to diagnose latrodectism.
The serum creatine kinase, serum glucose, alanine transaminase, aspartate transaminase, and peripheral white blood cell count may be elevated, [12] but these findings are nonspecific and generally unhelpful.
In a female patient, a pregnancy test should be performed to differentiate the presentation from premature labor or other complications of pregnancy and to guide the medication choice for treatment of latrodectism.
Imaging Studies
Plain radiographs of the affected limb may be indicated to evaluate for subcutaneous air if a concern for necrotizing fasciitis exists.
Venous Doppler ultrasonography of the affected extremity may be indicated to evaluate for deep vein thrombosis if the diagnosis is unclear.
Other Tests
A 12-lead ECG should be obtained in patients with autonomic instability, chest pain, or if comorbidities are present.
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Female redback spider showing a distinctive red stripe over the abdomen. Image courtesy of John Paterson.
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Female redback spider with egg sacs. Image courtesy of John Paterson.
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Female redback spider. Image courtesy of John Paterson.
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Female redback spider. Image courtesy of John Paterson.
