A method of detection of a status of cells within a cell culture is described. The method is based on comparing an IR spectrum of a test sample obtained from the cell culture with an IR spectrum of a control sample or samples or with an IR spectrum of a sample or samples obtained at an earlier time point in the cell culture and correlating differences between the spectra with the status of the cells. The status may be classified into healthy or unhealthy. The test sample may or may not contain cells. The test sample may contain cell fragments, cell components or cell media, or may be cell supernatant. The comparison may be performed using a predictive model based on pattern recognition algorithms, such as support vector machines SVM, linear discriminant analysis LDA, principal component discriminant function analysis PC-DFA, neural networks, or random forests). The analysis results may be used to monitor and/or control the cell culturing process.