A method of deriving actual available net volume in a container containing a liquid comprising: receiving, by a processor, container identification data from a container inspection unit that analyzes a container containing a liquid; receiving, by the processor, liquid level detection raw data from a liquid level detection unit that analyzes the container containing the liquid; the liquid level detection unit being able to detect different levels for different layers of liquids and solid substances; and determining a liquid level detection result for the liquid in the container, based at least on the container identification data and the liquid level detection raw data, receiving, by the processor, additional data from the container inspection unit; cross-checking, by the processor, the liquid level detection result with the additional data received from the container inspection unit, and generating, by the processor, a combined result of the container inspection unit and the liquid level detection unit after cross-checking the liquid level detection result, said combined result including volume information including an actual available net sample volume, the method being characterized in that the actual available net volume is derived by considering an offset value for unusable liquids and container type information including information about physical characteristics of the sample container, said offset value being determined by detecting layer transition characteristics in the transition areas of two layers in the sample, assigning a separation score or confidence level to each transition and using the confidence level to calculate the offset value. receiving, by a processor, container identification data from a container inspection unit that analyzes a container containing a liquid; receiving, by the processor, liquid level detection raw data from a liquid level detection unit that analyzes the container containing the liquid; the liquid level detection unit being able to detect different levels for different layers of liquids and solid substances; and determining a liquid level detection result for the liquid in the container, based at least on the container identification data and the liquid level detection raw data, receiving, by the processor, additional data from the container inspection unit; cross-checking, by the processor, the liquid level detection result with the additional data received from the container inspection unit, and generating, by the processor, a combined result of the container inspection unit and the liquid level detection unit after cross-checking the liquid level detection result, said combined result including volume information including an actual available net sample volume, the method being characterized in that the actual available net volume is derived by considering an offset value for unusable liquids and container type information including information about physical characteristics of the sample container, said offset value being determined by detecting layer transition characteristics in the transition areas of two layers in the sample, assigning a separation score or confidence level to each transition and using the confidence level to calculate the offset value.