In this sense, the
criteria for evaluating the accuracy were as follows: relative error
(RE) value should be within 15% of the spiked value except at LOQ,
where it should not deviate by more than 20%. The regression
equations with a weighting factor of 1/x (where x ¼ concentration)
were judged to produce the best fit for the concentration-detector
ratio response for all ARV in plasma.