Table 1:

Tympanometric classification* (based on a modified Jerger classification32,33) and interpretation34

TypeMiddle-ear pressure, daPaTympanogramInterpretation
A200 to −99Peak in this rangeNormal
C1−100 to −199Peak in this rangeNormal
C2−200 to −399Peak in this rangePositive predictive value of 54% for otitis media with effusion
B≥ −400Flat trace without a discernible peakPositive predictive value of 88% for otitis media with effusion
  • Note: daPa = decapascal.

  • * As used in primary care trials9,10 and a Cochrane systematic review.28

  • With normal canal volumes. Excessive wax, perforation and grommets excluded.