Development and Application of a LC-MS/MS Method for Simultaneous Quantification of Four First-Line Antituberculosis Drugs in Human Serum

Table 4

Recovery and matrix effect of four analytes in QC sample at three levels (n = 6).

Analytes	QC levels	Recovery (%)	Matrix effect
PZA	Low	87.04	0.99 ± 0.08
	Medium	91.25	0.99 ± 0.04
	High	90.80	1.01 ± 0.05
INH	Low	79.24	0.87 ± 0.04
	Medium	89.56	0.92 ± 0.05
	High	81.68	0.95 ± 0.03
EMB	Low	83.35	0.96 ± 0.04
	Medium	87.46	1.00 ± 0.03
	High	86.58	1.01 ± 0.04
RFP	Low	95.01	0.97 ± 0.12
	Medium	89.70	1.05 ± 0.06
	High	94.16	0.99 ± 0.05

PZA: pyrazinamide, INH: isoniazid, RFP: rifampicin, EMB: ethambutol, and QC: quality control.