**32. Diagnosis**

The diagnosis of AFE is "clinical" and one of exclusion. AFE should be suspected if a woman experiences one or more of the following during late pregnancy or within 48 hours of delivery: acute or sudden onset of hypotension and/or cardiac arrest, hypoxemia, seizures or coma, DIC and in absence of potential alternative explanation for these manifestations (Table 2). Demonstration of fetal squamous cells in pulmonary arterial circulation is not pathognomonic. Presence of AF cells in BAL may be supportive. There are no specific laboratory tests for diagnosing AFE. Diagnostic markers for AFE have been developed which rely on detection of fetal or amniotic fluid constituents in maternal circulation, such as Serum Sialyl Tn Antigen, (Benson et al., 2001; Kobayashi et al., 1993; Oi et al., 1998) and plasma zinc coproporphyrin (a component of meconium) (Kanayama et al., 1992). Serum Tryptase, a marker of mast cell degranulation may be elevated but unreliable (Dorne et al., 2002; Farrar & Gherman, 2001; Marcus et al., 2005; Nishio et al., 2002).
