In biochemical processes, the stoichiometry can be the result of macroscopic balances (where the microorganism is specified by the elementary composition and only the chemical reactions of the conversion process are considered) or the balances of the metabolic pathway, where biochemical knowledge available for metabolic reactions, in addition to the chemical characteristics of the system, are considered. It is possible to identify several linear relationships among the conversion rates in these processes. While several rates are measured, others can be calculated. If a calculated conversion rate is also measured, measurement errors or errors of the described model can be detected or even diagnosed by comparing these values, and accurate estimates can be obtained by combining them.