OBJECTIVE: To determine the accuracy of the TM-2430 blood pressure monitor, recently developed by the A&D company. DESIGN: Evaluation was performed using the 1990 and 1993 British Hypertension Society (BHS) protocols. Monitor's performance was assessed in relation to subjects' age, sex, level of blood pressure, and degree of adiposity. METHODS: Three TM-2430 recorders were assessed according to the various phases of the protocols. Simultaneous, same-arm readings were taken for the main validation test. Outcome was classified according to the criteria from the 1990 BHS recommendations, which are based on the cumulative percentage of readings differing from the mercury sphygmomanometer standard by 5, 10, and 15 mmHg or less, and using the criteria of the Association for the Advancement of Medical Instrumentation protocol, which considers a device accurate when the mean device-observer difference is within 5 mmHg and the related SD < 8 mmHg. RESULTS: During in-use assessment 2.3% of total measurements (N = 3744) were rejected automatically by the machine and another 5.5% werre discarded after visual inspection. The main validation test was performed with 98 subjects for a total of 595 blood pressure measurements. On the basis of the percentages of measurements differing from the mercury sphygmomanometer standard by </= 5, </= 10, and </= 15 mmHg, the TM-2430 device was graded A both for systolic blood pressure and for diastolic blood pressure. Differences between mean blood pressures as measured by device and observer were 2.2 +/- 3.9 mmHg for systolic blood pressure and 0.7 +/- 4.4 mmHg for diastolic blood pressure. The device's performance did not vary according to subjects' age, sex, and body mass, and was slightly better for subjects with high blood pressures and lean arms. CONCLUSION: These data show that the A&D TM-2430 monitor satisfies the recommended BHS and Association for Advancement of Medical Instrumentation accuracy levels for both systolic and diastolic blood pressures.