Diagnosis of Allergic Bronchopulmonary Aspergillosis: A Case-Based Approach

Sahajal Dhooria; Ritesh Agarwal


Future Microbiol. 2014;9(10):1195-1208. 

In This Article

What Is the Next Investigation for an Asthma Patient Found to Be Sensitized to A. fumigatus?

The next best step in the algorithmic workup of ABPA is total serum IgE (Box 4).

Total Serum IgE Levels

The serum total IgE level is a valuable test both in the initial diagnosis, and during follow-up of ABPA. A patient's current symptoms cannot be attributed to ABPA in the face of a normal serum IgE (provided that the patient is not on systemic glucocorticoid therapy).[2] As for specific IgE, the cutoff value of IgE level that should be used for diagnosis of ABPA remains uncertain. This is due to the fact that the levels of IgE overlap between normal individuals, atopic individuals (with or without fungal sensitization) and ABPA.[34] In 1970, Heiner et al. reported raised IgE values in patients with allergic aspergillosis.[35] The original paper published in 1977, describing the criteria proposed by the Patterson group did not provide a cutoff for total IgE.[4] The same group suggested a cutoff of 1500 ng/ml in 1978,[24] while it was stated as 2500 ng/ml (for the acute stage) in 1982.[36] In 1986, they proposed that an IgE <1000 ng/ml along with an absence of Aspergillus precipitins probably excluded ABPA while in those with IgE >2000 ng/ml and presence of precipitins, determination of A. fumigatus specific IgE (and IgG levels) was required.[37] The Northwestern Allergy Immunology series of ABPA used an IgE cutoff of 1000 ng/ml.[38] Later series have used a cutoff of 1000 IU/ml for diagnosing ABPA in asthma too.[9,30,39,40] In a latent-class analysis, a cutoff of 1000 IU/ml gave a sensitivity and specificity of 92 and 40%, respectively, whereas using a value of 417 IU/ml (1000 ng/ml) reduced the specificity to 24% with only a marginal increase in sensitivity to 96%.[8] The latest expert guideline therefore recommends the use of a 1000 IU/ml cutoff for the diagnosis of ABPA.[7]