A method for diagnosing a body malfunction is provided. At least one change in urinary parameter values, being indicative of the body malfunction, is monitored and detected. A volumetric urinary output of kidneys is monitored using a urine flow monitoring apparatus having a low flow metering device. It is determined whether a change exists in at least one of a volume value of the volumetric urinary output, and a trend of the corresponding urinary parameter value during a predetermined period. Signals are received from a plurality of electrodes, representing the urinary parameter values. The body malfunction is detected based on the determination of the change in at least one of the volume value and the trend.