Objective. This study aimed at evaluating the diagnostic accuracy of a consumer model acoustic reflectometer in the hands of parents in the detection of middle-ear fluid among children. Design. Prospective diagnostic study according to STARD guidelines. Acoustic reflectometry recorded by the parents was compared with otomicroscopic myringotomy with suction in general anaesthesia, performed immediately afterwards. Setting. Secondary care (Kanta-Häme Central Hospital, Finland). Patients. Pre-school (B7 years) children undergoing otomicroscopic myringotomy due to recurrent acute otitis media or suspicion of glue ear. Main outcome measures. Sensitivity, specificity, and positive and negative predictive values of acoustic reflectometry. Results. Consumer model acoustic reflectometry performed by parents reached sensitivity of 94% (95% confidence interval 88Á100%) and negative predictive value of 92% (83Á100%) with result 1 (green colour) on a scale of 1Á5. On the other hand, the method was not very specific and positive predictive value was poor. Conclusions. The negative screening result was very reliable. Thus, home screening of otitis among otitis-prone children and home follow-up of resolution of middle-ear fluid afterwards deserves to be studied in the home setting in the future.Key Words: Acoustic reflectometry, diagnosis, middle-ear fluid, otitis media, sensitivity, specificity Acoustic reflectometry (AR) is a method of assessing the probability of middle-ear fluid (MEF) by an instrument emitting a sound frequency spectrum sweep to the tympanic membrane and analysing the intensity and frequency spectrum of the reflecting sound [1]. The acoustic reflectometer is a small, lightweight, and cordless instrument, the tip of which is inserted at the end of the ear canal and directed towards tympanic membrane during recording, which takes approximately five seconds. It is generally easy to perform and has a high success rate even among crying and struggling children [2], suggesting a possibility for home usage by parents. Newer second-generation acoustic reflectometry (SG-AR) has been proved to be comparable to tympanometry in detecting MEF among children younger than two years [3]. In our previous study [4], SG-AR in the hands of nurses reached a sensitivity and specificity of 96% and 87% among children. Home monitoring with AR was studied by Barnett et al. [5]: parents were able to obtain valid readings in 80% of attempts. The professional SG-AR model used in the above-mentioned studies was followed by a consumer model. Block et al. demonstrated that parents are capable of using the consumer AR device, taking accurate readings, and interpreting them [6]. Moreover, the AR readings made by parents showed good concordance with those obtained by trained nurses. In our recent Prior to the present study, the diagnostic capability of a consumer model acoustic reflectometer has not been validated in the hands of layman consumers, e.g. parents.. Negative screening result obtained by parents, indicating healthy ear, p...