ANSI S3.21 : 2004

1 Scope
  1.1 Purpose of standard
  1.2 Limit of standard
  1.3 Modifications of standard procedures
  1.4 Source
2 Normative References
3 Definitions
4 General Requirements
  4.1 Ear canal
  4.2 Earphone placement
  4.3 Instructions
  4.4 Response task
  4.5 Interpretation of response
      4.5.1 On response and off response
      4.5.2 Latency of response
      4.5.3 False responses
5 Determination of threshold
  5.1 Familiarization procedure
  5.2 Determination of threshold
      5.2.1 Tone duration
      5.2.2 Interval between tones
      5.2.3 Level of first presentation
      5.2.4 Levels of succeeding presentations
      5.2.5 Threshold of hearing
6 Standard Procedures for Air-Conduction Measures
  6.1 Test environment
  6.2 Instrumentation and calibration
  6.3 Frequency
  6.4 Order
  6.5 Masking in air-conduction audiometry
  6.6 Recording of result
      6.6.1 Audiogram form
      6.6.2 Audiogram Symbols
      6.6.3 Other information
7 Standard Procedures for Bone-Conduction Measures in
  Diagnostic Audiometry
  7.1 Instrumentation
  7.2 Calibration
  7.3 Vibrator placement
  7.4 Covering of ear
  7.5 Frequencies
  7.6 Order
  7.7 Masking
  7.8 Recording of results
Annex A (normative) - Audiogram Symbols
  A.1 Air-conduction symbols
  A.2 Bone-conduction symbols
  A.3 Symbols representation
  A.4 Multiple notation
  A.5 No response
  A.6 Separate forms
  A.7 Lines connecting symbols
  A.8 Color coding
Annex B (informative) - Variability of Threshold Measures
  B.1 General information
Figures

Describes the procedure used in the assessment of an individual's threshold of hearing for pure tones. Pure-tone threshold audiometry includes manual air-conduction measurements at octave intervals from 250 through 8000 Hz and at intermediate frequencies as needed.