A method for detecting aspiration in a clinical analyzer comprising a tubing , a pressure transducer , a liquid vessel , a probe and a pump for performing an aspiration into the probe, wherein a liquid is used as a working fluid to couple the pump to the probe, comprising: acquiring, from the pressure transducer , aspiration pressure measurement data; transforming the pressure measurement data into frequency domain data; generating a clean version of the frequency domain data by attenuating, using a filter, unwanted frequencies; wherein a digital implementation of a 2 nd order Butterworth low pass filter takes the form of: y i = a 0 x i + a 1 x i − 1 + a 2 x i − 2 − b 1 y i − 1 − b 2 y i − 2 , wherein: y[n] = filtered data x[n] = unfiltered data a n , b n = filter coefficients wherein individual filters for acceleration, slew, and deceleration phases of the pump motion are used, wherein the filter coefficients are defined by a desired cutoff frequency and the sampling rate; and wherein the filters are adjusted to create a higher attenuation of frequencies above the cutoff frequency if oscillating noise persists, transforming the cleaned version of the frequency domain data into time domain data; characterised by calculating from the time domain data metrics derived from the data describing the aspirated fluid properties of viscosity, density, and a goodness of fit measure from an expected aspiration curve. comparing the calculated metric values to a calibrated or pre-determined range for said metrics; and determining, based on the comparison, if an aspiration was properly performed. acquiring, from the pressure transducer , aspiration pressure measurement data; transforming the pressure measurement data into frequency domain data; generating a clean version of the frequency domain data by attenuating, using a filter, unwanted frequencies; wherein a digital implementation of a 2 nd order Butterworth low pass filter takes the form of: y i = a 0 x i + a 1 x i − 1 + a 2 x i − 2 − b 1 y i − 1 − b 2 y i − 2 , wherein: y[n] = filtered data x[n] = unfiltered data a n , b n = filter coefficients wherein individual filters for acceleration, slew, and deceleration phases of the pump motion are used, wherein the filter coefficients are defined by a desired cutoff frequency and the sampling rate; and wherein the filters are adjusted to create a higher attenuation of frequencies above the cutoff frequency if oscillating noise persists, y[n] = filtered data x[n] = unfiltered data a n , b n = filter coefficients wherein individual filters for acceleration, slew, and deceleration phases of the pump motion are used, wherein the filter coefficients are defined by a desired cutoff frequency and the sampling rate; and wherein the filters are adjusted to create a higher attenuation of frequencies above the cutoff frequency if oscillating noise persists, transforming the cleaned version of the frequency domain data into time domain data; characterised by calculating from the time domain data metrics derived from the data describing the aspirated fluid properties of viscosity, density, and a goodness of fit measure from an expected aspiration curve. comparing the calculated metric values to a calibrated or pre-determined range for said metrics; and determining, based on the comparison, if an aspiration was properly performed. <EOS>