Methods for the evaluation of the accidental coincidences counting rates in triple-to-double coincidences ratio (TDCR) liquid scintillation (LS) measurements have been proposed recently. This study shows how these corrections can be extended to two detector systems, such as commercial LS counters, or four-detector systems used for the compton source efficiency tracing (CSET) method. The significance of performing corrections for accidental coincidences in low-activity LS counting or TDCR measurements is demonstrated. The impact of accidental coincidences on the determination of half-life of radioisotopes is also shown.