A hand-held pipette instrument (100, 140, 152, 210), the pipette instrument comprising: an installed removable pipette tip (114, 162); and a body carrying: a source of suction (120, 142); a pipette tip interface configured to hold said installed removable pipette tip (114, 162) and to place said installed removable pipette tip (114, 162) into communication with said source of suction (120, 142); and a source of electrical energy in operable association with: a display panel capable of visually presenting information to a user; and a microprocessor and an associated memory (130, 172); wherein: said pipette tip interface is further structured and arranged to dispose said installed removable pipette tip (114, 162) in communication with interrogation circuitry (132, 170) carried by said body and configured to receive an input signal from said installed removable pipette tip, said interrogation circuitry (132, 170) being adapted for particle counting by detection of signals resulting from Stokes-shift phenomena occurring in said installed removable pipette tip (114, 162) and/or said interrogation circuitry (132, 170) is adapted for particle counting by detection of signals resulting from Coulter principle phenomena occurring in said installed removable pipette tip (114, 162), wherein the pipette instrument is configured to enable in use a lower voltage threshold boundary and an upper voltage threshold boundary of the detected signals to be selected and wherein the pipette instrument is configured to calculate a particle count based upon data collected between the selected boundaries. an installed removable pipette tip (114, 162); and a body carrying: a source of suction (120, 142); a pipette tip interface configured to hold said installed removable pipette tip (114, 162) and to place said installed removable pipette tip (114, 162) into communication with said source of suction (120, 142); and a source of electrical energy in operable association with: a display panel capable of visually presenting information to a user; and a microprocessor and an associated memory (130, 172); wherein: said pipette tip interface is further structured and arranged to dispose said installed removable pipette tip (114, 162) in communication with interrogation circuitry (132, 170) carried by said body and configured to receive an input signal from said installed removable pipette tip, said interrogation circuitry (132, 170) being adapted for particle counting by detection of signals resulting from Stokes-shift phenomena occurring in said installed removable pipette tip (114, 162) and/or said interrogation circuitry (132, 170) is adapted for particle counting by detection of signals resulting from Coulter principle phenomena occurring in said installed removable pipette tip (114, 162), wherein the pipette instrument is configured to enable in use a lower voltage threshold boundary and an upper voltage threshold boundary of the detected signals to be selected and wherein the pipette instrument is configured to calculate a particle count based upon data collected between the selected boundaries. a source of suction (120, 142); a pipette tip interface configured to hold said installed removable pipette tip (114, 162) and to place said installed removable pipette tip (114, 162) into communication with said source of suction (120, 142); and a source of electrical energy in operable association with: a display panel capable of visually presenting information to a user; and a microprocessor and an associated memory (130, 172); wherein: said pipette tip interface is further structured and arranged to dispose said installed removable pipette tip (114, 162) in communication with interrogation circuitry (132, 170) carried by said body and configured to receive an input signal from said installed removable pipette tip, said interrogation circuitry (132, 170) being adapted for particle counting by detection of signals resulting from Stokes-shift phenomena occurring in said installed removable pipette tip (114, 162) and/or said interrogation circuitry (132, 170) is adapted for particle counting by detection of signals resulting from Coulter principle phenomena occurring in said installed removable pipette tip (114, 162), wherein the pipette instrument is configured to enable in use a lower voltage threshold boundary and an upper voltage threshold boundary of the detected signals to be selected and wherein the pipette instrument is configured to calculate a particle count based upon data collected between the selected boundaries. a display panel capable of visually presenting information to a user; and a microprocessor and an associated memory (130, 172); wherein: said pipette tip interface is further structured and arranged to dispose said installed removable pipette tip (114, 162) in communication with interrogation circuitry (132, 170) carried by said body and configured to receive an input signal from said installed removable pipette tip, said interrogation circuitry (132, 170) being adapted for particle counting by detection of signals resulting from Stokes-shift phenomena occurring in said installed removable pipette tip (114, 162) and/or said interrogation circuitry (132, 170) is adapted for particle counting by detection of signals resulting from Coulter principle phenomena occurring in said installed removable pipette tip (114, 162), wherein the pipette instrument is configured to enable in use a lower voltage threshold boundary and an upper voltage threshold boundary of the detected signals to be selected and wherein the pipette instrument is configured to calculate a particle count based upon data collected between the selected boundaries.