OBJECTIVE: To establish a method for the determination of nitrofurazone in nitrofurazone and zinc oxide liniment. METHODS: The content of nitrofurazone was determined by UV spectrophotometry. The solvent was water and the wavelength was 375nm. RESULTS: There was good linear relationship within the concentration range of 1.05～12.60?g?mL-1(r=0.999 8). The average recovery was 100.9%,RSD=0.07%. CONCLUSION: The method was sensitive, accurate, reliable, reproducible, and suitable for quality control of nitrofurazone in nitrofurazone and zinc oxide liniment.

Purpose To evaluate the correlation and consistency of left ventricular ejection fraction (LVEF) obtained by ECG-gated myocardial perfusion SPECT (GMPS) using four formulae (R0-R3) of ECToolbox software and findings on equilibrium radionuclide angiography (ERNA), and to determine the optimal diagnostic thresholds by using the four formulae. Materials and Methods A total of 38 patients with myocardial infarction and 65 patients with suspected coronary heart disease underwent both 99Tcm-MIBI rest GMPS and 99Tcm-RBC ERNA within a week. The LVEF values calculated by ECToolbox R0, R1, R2 and R3 were compared with those obtained by ERNA, and compared with ERNA results, the optimal diagnostic thresholds of the four formulae (R0-R3) were assessed by receiver operating characteristic (ROC) curves. Results The results calculated by the formulae (R0-R3) presented a significant positive correlation with that obtained by ERNA [mean LVEF value by ERNA (54.6±17.5)%, mean LVEF value by formulae R0-R3 (64.1±15.7)%, (56.3±15.1)%, (69.9±17.9)% and (56.7±13.6)%, respectively, r=0.899, 0.898, 0.890, 0.895; P<0.01]. All mean LVEF values calculated by the four formulae were higher than that by ERNA, and the difference was significant (P<0.05). LVEF≥50%obtained by ERNA was considered as normal diagnostic value, the optimal diagnostic thresholds of R0-R3 were 56.5%, 51.5%, 64.5% and 52.5%, respectively. Conclusion The results calculated by R0, R1, R2 and R3 in the ECToolbox software and that by ERNA show significant correlation and difference for the assessment of LVEF. Thus it is advisable to stick to one formula in the follow-up of each patient and select correspondent threshold in the clinical diagnosis.

Objective To evaluate the efficacy and safety of linezolid in empirical treatment of methicillin-resistant Staphylococcus (MRS) pneumonia. Methods One hundred and thirty-five hospitalized patients with MSR pneumonia receiving linezolid from April 2009 to October 2010 were enrolled in this retrospective cohort study, and all subjects were assigned to two groups: 75 cases with empirical treatment (linezolid 0. 6 g by infusion q12h at admission) , and 60 cases with objective treatment (linezolid after the sputum culture). The severity score, clinical effect and adverse effect were observed, and the therapeutic effects in patients with high risk factors were especially evaluated. SPSS13.0 software was used for statistical analysis. Results The scores were decreased significantly after finishing therapeutic causes for 3 and 7 days in both groups (tempirical =12.29 and 16.53, tobjective =9.36 and 11.49, P<0. 05). There were significant differences in severity scores after 3 and 7 days between empirical and objective treatment groups (t =2. 64 and 3. 08, P < 0. 01). There were significant differences in absorption time, length of ICU and total hospital stay between two groups (t =6. 61 , 4. 39 and 10. 25, P <0. 05). In empirical and objective group, the effective rates were 88.0% (66/75) and 83.3% (50/60) (x2 = 0.60, P > 0.05 ). In the patients with high risk factors, the effective rates of two groups were 86. 8% (33/38) and 63. 6% (14/22) , and the difference was significant (x2 =4.42, P<0.05). The rate of adverse effects were 6.7% (5/75) in empirical group and 5.0% (3/60) in objective group, and the difference was not significant (x2 =0. 17, P > 0. 05). Conclusion Linezolid can be used as empirical treatment for MRS pneumonia with rapid symptoms relieve and high efficacy, especially for patients with high risk.

Objective To develop a candidate reference method for the measurement of serum glucose based on isotope dilution liquid chromatography tandem mass spectrometry(ID-LC/MS/MS)Methods An internal standard [~(13)C_6]glucose was added to serum samples and equilibrated with endogenous glucose.Serum proteins were removed by a precipitation with anhydrous ethanol.Serum glucose and the internal standard were then reacted with 1-phenyl-3-methyl-5-pyrazolone and the formed derivatives were analyzed by liquid chromatography tandem mass spectrometry with multiple reaction monitoring(MRM).The method was calibrated with bracketing calibrators and serum glucose concentrations were calculated by comparing the peak area ratios of samples with that of the calibrators.Results The within-run,between-run and total coefficients of variation averaged 0.36%,0.47%and 0.61%,respectively.The analytical recoveries ranged from 99.0% to 100.9%.Results of analyzing the certified reference material SRM 965a showed an average biases of-0.20%.Conclusions An ID-LC/MS/MS method for measuring serum glucose has been developed.The method is highly precise and accurate and may be used as a candidate reference method.

Objective To exlore the influence of internal quality control and external quality control assessment(EQA) resulting from applicability of control samples in measurement of whole blood viscosity (WBV) through the analysis and comparison of applicability of 1 non-Newtonian fluid internal quality control sample in 3 viscometers. Methods Viscometer B, C and D were used to measure WBV of 30 blood samples in parallel under the shear rate(SR) of 1 s-1,30 s~(-1) and 200 s~(-1), then the blood SR-WBV curves of 3 viscometers were drawn according to the results. At the same time, viscometers B, C and D were used respectively to determine the WBV of control A 10 times in one day, then the control A SR-WBV curves were mapped. Three viscometers were used to measure the manufactory control samples and control A 5 times in one day for 4 days. Four groups of daily values of manufactory control samples and control A of each instrument were used to carry out F test to calculate whether 4 daily values are difference. Finally, the control A was dispensed in 49 laboratories nationwide chosen for measurement. On the basis of viscometer used, 20 laboratories were classified as group B, 20 laboratories were classified as group C and 9 laboratories were classified as group D. Then the data under SR of 1 s~(-1) were analyzed to calculate the coefficient of variation (CV) in the group. Results There was significant difference among the WBV of blood samples measured by the viscometers B, C and D. The results under SR of 1 s~(-1) declined in turn, and they were highest under SR of 30 s~(-1) followed by the values of viscometer D and B and they were (8.14±0.75), highest under SR of 30 s-1 followed by the values of viscometer B and D, and they were (7.35±0.07), daily values of manufactory control and control A of each instruments in four groups were compared. Under SR of 1 s~(-1), there was no difference between daily values of manufactory control and control A in viscometer B (F = 2.63, 1.37, P > 0.05), and there was no difference of daily values of manufactory control among viscometer C and D (F = 0.33,3. 14, P > 0.05), but significant daily difference existed when control A was tested by viscometer C and D (F = 5.76, 8.00, P < 0.05). Under SR of 30 s~(-1), there was no difference of daily values of manufactory control among 3 viscometers(F =0.31, 0.18, 2.26, P >0.05), and there was no difference of daily values of control A among 3 viscometers' (F = 1.03, 1.83, 2.40, P > 0.05); Under SR of 200 s~(-1), there was no difference of daily values of manufactory control among 3 viscometers (F =2.59, 0.68, 2.96, P > 0.05), and there was no difference of daily values of control A among 3 viscometers (F=2.31, 3.01, 2.28, P>0.05). When control A was tested under SR of 1 s~(-1) in 49 laboratories nationwide, the WBV values in groups of viscometer B, C and D were (18.47±1.30), (11.17±2.38), viscometer D and C were 63.75% and 21.3%. Conclusions Control A could fully mimic the properties of whole blood steadily on viscometer B, but partially mimic viscometer C and D, so the control A is most appropriate for viscometer B. Because current non-Newtonian fluid internal quality control could mimic rheological properties of whole blood under specifically conditions, laboratories should evaluate the consistent degree between control and whole blood, only the candidates which can mimic the properties of whole blood approximately could be chosen as quality control of WBV. When third-party control is chosen to be samples of EQA, its applicability should be in consideration. Pretest should be performed adequately to define applicability of third-party control, so as to reduce the difference among laboratories due to applicability of control and reflect detection quality of laboratories exactly.

Objective To develop a candidate reference method for the measurement of creatinine in human serum based on isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS). Methods An isotopically labeled internal standard [<'2>H<,3>] creatinine was added to the serum sample and equilibrated with the endogenous creatinine. The samples were treated with anhydrous ethanol to remove proteins by precipitation. After being washed with chloroform for further clean-up, the samples were analyzed by LC/MS/MS. Serum creatinine was quantified by a bracketing calibration. Results The within-run, between-run and total coefficients of variation ranged from 0.52% to 0.61%, 0.11% to 0.59% and 0.61% to 0.83%, and the averages were 0.57%, 0.43% and 0.73%, respectively. The analytical recoveries ranged from 99.09% to 101.13% with an average of 100.3%.The results of analyzing the certified reference material SRM 909b (Level Ⅰ and Ⅱ) and SRM 967b showed biases of less than 0.4%. Conclusions An ID-LC/MS/MS method for measuring serum creatinine has been developed. The method is highly precise and accurate and may be used as a candidate reference method for serum creatinine measurements.

Objective To develop a candidate reference method for the measurement of urea in human serum based on isotope dilution/gas chromatography/mass spectrometry.Methods [13C,15N2]Urea used as internal standard Was added to the serum sample and equilibrated with endogenous nonlabeled urea.The serum samples were treated with anhydrous ethanol to emove proteins by precipitation.The serum urea and labeled urea were converted into a trimethylsilyl derivative of 2-hydroxypyrimidine and analyzed by gas chromatography/mass spectrometry system with selected ion monitoring.The concentration of serum ureaWas calculated by the theory of bracketing method.Results The average value of within-run oefficient of vailation(CV),between-run CV and total CV of the procedure were 0.38%(ranged from 0.12%to 0.47%),O.62%(ranged form 0.49% to 0.87%)and 0.73%(ranged from 0.51% to 0.93%).Respectively.The analytical recoveries ranged from 99.37% to 100.95%.The resuhs of analyzing the certified refefence material SRM909b(Level Ⅰand Ⅱ)showed a bias less than 0.2%.Conclusion The procedure for measuring urea in serum is a highly accurate and precise method and can be used as a candidate reference method for serum urea assays.

Objective To evaluate the matrix effect of processed materials in serum total glycerol measurement and to assess the accuracy of routine test systems.Methods With an isotope dilution liquid chromatography tandem mass spectrometry method as the comparative method，matrix effects of 28 processed materials on 8 routine test systems were evaluated ccording to the NCCLS EP 14 protocol.The processed materials and 20 flesh patient specimens were analyzed with both the comparative method and each of the evaluated methods and results obtained with the two methods were plotted.Two-tailed 95% prediction intervals for the mean of the flesh patient specimen were computed and results on the processed aterials were compared with these intervals for evaluation of matrix effect.Results with the two methods on fresh samples were also compared for assessment of the accuracy of the routine test systems.Results Some of the processed samples showed matrix effects on some of the routine test systems.The observed matrix effects were system-specific and aused either positive or negative biases.Calibration biases were also observed on some test systems.Conclusion Matrix effect and calibration bias have been observed in serum total glycerol measurements.Continued efforts are needed for improving the accuracy of serum total glycerol measurements.

Objective To evaluate the matrix effects in serum urea measurements of external quality assessment(EQA)materials and commercial reference materials(calibrators or controls)on enzymatic methods and to verify the trueness of the enzymatic methods.Methods The Clinical and Laboratory Stadards Institute(CLSI)EP 14-A2 protocol was used for the evaluation of matrix effect.An isotope dilution gas chromatography mass spectrometry method was used as the comparative method.Twenty five fresh patient serum samples,15 EQA materials and 13 calibrators or controls were analyzed with 7 enzymatic methods (evaluated methods)and the comparative method and results were processed according to the protocol. The trueness of the evaluated methods were also assessed by comparing the fresh sample results obtained with the evaluated and comparative methods.Results Eight of 15 EQA materials and 3 of 13 calibrators or controls showed no matrix effects on all the 7 routine methods.One processed sample showed matrix effect on all the routine methods.Method dependent matrix effects of other materials were observed on other materials.Calibration biases were also observed on some enzymatic methods.Conclusions Matrix effects and calibration bias have been observed in serum urea measurements.Continued efforts are needed for improving the accuracy and the comparability of serum urea measurements.

Objective To evaluate the commutability of certified reference materials, external quality assessment program materials and calibrators for serum glucose measurements which were performed in 24 routine measurement procedures.Methods 35 fresh patient specimens and some reference materials were analyzed by isotope dilution liquid chromatography tandem mass spectrometry ( as the comparative method) and 24 routine measurement procedures (as the evaluated methods).The relationships between the results from the evaluated method and the comparative methods were evaluated to identify the commutability.Results It showed that 5 certified reference materials, 2 trueness verification materials, and 5 calibrators were commutable in all 24 routine measurement procedures.The other samples were displayed the presence of commutability issue in different degrees.Conclusion It is important to pay more attention to the problems brought by commutability of reference materials in clinical laboratory.