Mast Cell Activation Syndrome: Improved Identification by Combined Determinations of Serum Tryptase and 24-Hour Urine 11β-Prostaglandin2α

We recommend measurement of 24-hour urine 11β-PGF2α and serum tryptase levels of patients with symptoms suggestive of MCAS. Measurement of 24-hour urine 11β-PGF2α and serum tryptase levels can help avoid misdiagnosis and overinterpretation of MCAS symptoms in clinical practice. Given that an elevation of 24-hour urine N-MH level was found only in 2 patients, measurement of this mediator may be less helpful in diagnosing MCAS. We recommend aspirin therapy for patients with MCAS and with elevated 24-hour urine 11β-PGF2α levels.