ABSTRACT
Lead poisoning severely threatens human health with its cumulation and durability in the body. The analysis of lead in blood is vital for screening, diagnosis, treatment, and prognostication of lead poisoning and for indirectly monitoring the level of lead in the environment. Although the detection programs are available throughout our country, the accuracy and comparability of the results cannot meet the expectation. A variety of factors can affect the accuracy of blood lead testing. To promote the application of blood lead analysis in clinical trials and reduce the bias of results, a better reference system for blood lead analysis should be established to evaluate the accuracy of traditional methods, promote the standardization of blood lead analysis and achieve accurate blood lead testing.
ABSTRACT
Objectives:To establish a candidate reference method of isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) for the determination of human plasma normetanephrine, and to evaluate the performance of the method. The method was used to quantify the samples of the external quality assessment program, and to initially evaluate the detection status of plasma normetanephrine.Methods:The isotope standard solution of normetanephrine was selected as the internal standard, the gravimetric method was used for sampling, and the standard curve method was used for quantification. Protein precipitation combined with weak cation solid phase extraction was used for pretreatment, and ultra-high liquid chromatography-coupled triple quadrupole mass spectrometry was used for LC/MS analysis. According to the relevant EP documents, the specificity, matrix effect, detection limit, quantification limit, precision, accuracy, and uncertainty of the method were estimated. This method is used to quantify the samples of the 2020 National Center for Clinical Laboratories external quality assessment program of normetanephrine. Taking the average value of this method as the target value, the optimal allowable total error standard of biological variation as the evaluation limit, the quality of the laboratory testing was evaluated.Results:The method had good specificity, and the interferences and matrix effects did not affect the detection results. The detection limit and quantification limit of plasma normetanephrine were 1.08 pg/g and 3.54 pg/g, respectively. The intra-batch coefficient of variation ( CV) and total CV were 0.43%-1.10% and 0.61%-1.42%, respectively. The relative recovery rates were 98.5%～101.9%. The relative expansion uncertainty of the four plasma samples were 3.10%, 2.34%, 2.16%, and 1.73%, respectively. The results of the external quality assessment program showed that the pass rates of the 202013 and 202014 samples were 80% and 85%, respectively. Conclusions:The study established a candidate reference method of ID-LC/MS/MS for the measurement of plasma normetanephrine. The method is accurate, precise and simple, and is expected to be used as a reference method for the determination of plasma normetanephrine, and can be applied to quantify the samples of the external quality assessment program.
ABSTRACT
Objective: To explore the value of virtual touch tissue imaging quantification (VTIQ) in evaluation of pre-and post-operative elasticity of incomplete acute closed ruptured Achilles tendon in young and middle-age men. Methods: A total of 32 patients with unilateral incomplete acute closed ruptured Achilles tendon were enrolled. VTIQ examination was performed on bilateral Achilles tendon for speed mode. Achilles tendon was divided into distal segment (5 cm above insertion at the attachment of Achilles tendon), middle segment (>5-10 cm above insertion at the attachment of Achilles tendon ) and proximal segment (from >10 cm above insertion at the attachment of Achilles tendon to musculotendinous junction). SWV was obtained, and then statistical analysis was performed in a neutral position 1 week before, 12 weeks and 24 weeks after operation. Results: SWV of ruptured Achilles tendon was lower than that of healthy side (all P<0.001), of distal segment was higher than of middle and proximal segment for bilateral Achilles tendon (all P<0.01). Twelve weeks after operation, SWV of the middle and distal segment of the healing Achilles tendon were both lower than the healthy side (both P<0.001), while 24 weeks after operation, SWV of distal segment of the healing Achilles tendon was lower than the healthy side (P<0.001). SWV of healing Achilles tendon gradually increased with time going, the difference between the two time points is statistically significant (all P<0.01). Conclusion: VTIQ can be used to quantitatively observe the elasticity of incomplete acute closed ruptured Achilles tendon pre-and post-operation, and provide objective evaluation indicators of Achilles tendon.