Device and method for determining a viability and/or a cell count of biological cells in a suspension by means of collimated transmission

A method for determining a viability and/or a cell count of biological cells in a cell suspension culture by means of a collimated transmission, the method comprising:

• illuminating a sample of the cell suspension culture with a collimated electromagnetic illumination beam;
• detecting an electromagnetic transmission beam being a portion of the collimated electromagnetic illumination beam which has been transmitted through the sample of the cell suspension culture;
• and
• determining the viability and/or the cell count of the biological cells based on the detected transmission beam,
• wherein the illumination beam and/or the transmission beam are/is manipulated such that an effective acceptance angle θa of the collimated transmission is equal to or below a specified threshold value, and
• wherein the effective acceptance angle θa is defined as the sum of:
• a maximal illumination beam divergence angle θ1 of the collimated electromagnetic illumination beam, and
• a maximal transmission beam detection angle θ2 of the transmission beam.