A device for estimating a mechanical property of a sample of blood, comprising: a chamber configured to hold the sample; a transmitter configured to transmit a plurality of waveforms, including at least one forcing waveform that carries sufficient energy to generate acoustic radiation force to the sample and induce motion and at least one sensing waveform having a lower energy than the forcing waveform; a transducer assembly operatively connected to the transmitter and configured to transform the transmitted waveforms into ultrasound waveforms, the transducer assembly further configured to transmit and receive ultrasound waveforms into and out of the chamber, and the transducer assembly further configured to transform at least two received ultrasound waveforms into received electrical waveforms; a data processor configured to: receive the received electrical waveforms; estimate a difference in the received electrical waveforms that results at least partially from movement of the sample; and characterized in that the data processor is further configured to: estimate a mechanical property including shear modulus associated with stiffness, of the sample by comparing at least one feature of the estimated difference to at least one predicted feature, wherein the at least one predicted feature is based on a model of an effect of the chamber wall; and a controller configured to control the timing of an ultrasound transmitter and the data processor, wherein the at least one predicted feature is based on an analytical model or a computational model, the model comprising at least one of i) a model of an aspect of an induced motion causing an induced displacement, wherein the induced motion is caused at least in part by a boundary effect of the chamber wall to alter the induced displacement compared to what would be expected if the same force were applied to an infinite or semi-infinite medium, ii) a model of an aspect of the induced motion that is caused at least in part by resonance within the chamber, and/or iii) a model of an aspect of the induced motion that is caused at least in part by reflection of an induced shear wave from the chamber wall. comprising: a chamber configured to hold the sample; a transmitter configured to transmit a plurality of waveforms, including at least one forcing waveform that carries sufficient energy to generate acoustic radiation force to the sample and induce motion and at least one sensing waveform having a lower energy than the forcing waveform; a transducer assembly operatively connected to the transmitter and configured to transform the transmitted waveforms into ultrasound waveforms, the transducer assembly further configured to transmit and receive ultrasound waveforms into and out of the chamber, and the transducer assembly further configured to transform at least two received ultrasound waveforms into received electrical waveforms; a data processor configured to: receive the received electrical waveforms; estimate a difference in the received electrical waveforms that results at least partially from movement of the sample; and receive the received electrical waveforms; estimate a difference in the received electrical waveforms that results at least partially from movement of the sample; and characterized in that the data processor is further configured to: estimate a mechanical property including shear modulus associated with stiffness, of the sample by comparing at least one feature of the estimated difference to at least one predicted feature, wherein the at least one predicted feature is based on a model of an effect of the chamber wall; and a controller configured to control the timing of an ultrasound transmitter and the data processor, wherein the at least one predicted feature is based on an analytical model or a computational model, the model comprising at least one of i) a model of an aspect of an induced motion causing an induced displacement, wherein the induced motion is caused at least in part by a boundary effect of the chamber wall to alter the induced displacement compared to what would be expected if the same force were applied to an infinite or semi-infinite medium, ii) a model of an aspect of the induced motion that is caused at least in part by resonance within the chamber, and/or iii) a model of an aspect of the induced motion that is caused at least in part by reflection of an induced shear wave from the chamber wall. i) a model of an aspect of an induced motion causing an induced displacement, wherein the induced motion is caused at least in part by a boundary effect of the chamber wall to alter the induced displacement compared to what would be expected if the same force were applied to an infinite or semi-infinite medium, ii) a model of an aspect of the induced motion that is caused at least in part by resonance within the chamber, and/or iii) a model of an aspect of the induced motion that is caused at least in part by reflection of an induced shear wave from the chamber wall.