Even when samples are carefully chopped up and homogenized, variations in potency measurements of about 20% are not uncommon. A European
study involving 40 labs found that around one third of results were either more than 29% greater or more than 29% lower than the mean value. Even worse precision could be expected if the measurement error, caused by the sampling and extraction process, were to be included.
Another study published in the United States showed that infrared spectroscopy can yield results with an accuracy of 1.5X to 2X greater than HPLC. This may be since infrared spectroscopy avoids the complex sample preparation necessary for HPLC analysis which is subject to human error. The GemmaCert device, based on spectroscopy, does not require any sample preparation for potency analysis. The risk of human error is removed and there is also $0 sample waste.