Clinical application of mass spectrometry technology has attracted the attention of clinical laboratory experts due to its high sensitivity, high specificity, and capacities of simultaneous detection of multiple compounds. In recent years, mass spectrometry technology has made significant achievements in the fields of identification of pathogenic microorganism, detection of trace elements and heavy metals, small molecule hormones, vitamins, amino acids, peptides and proteins, as well as therapeutic drug monitoring (TDM) and poisoning drugs screening. In order to further clarify the opportunities and challenges brought by this complex mass spectrometry technology in the field of clinical laboratory, the Chinese Journal of Laboratory Medicine invited experts and scholars of laboratory medicine to share their experience and opinions on related items focusing on the positioning of mass spectrometry technology in the clinical laboratory, the development and improvement of the clinical laboratory by mass spectrometry technology, the challenges of interpreting mass spectrometry test results, the challenges of operating and managing clinical mass spectrometry laboratories, and ways of improving the application of clinical mass spectrometry laboratories with this technology. Agreement was achieved in that the introduction of mass spectrometry technology into the clinical laboratory could bring new directions and opportunities for clinical testing and research, and also is associated with a series of challenges such as the difficulty of sample pretreatment, the high cost and complexity of mass spectrometry technology, the complexity of data processing and interpretation, the lack of standards and norms, and the issue of determining the price of mass spectrometry examinations.

Objective:To investigate the clinical, skeletal muscle pathological, and genetic characteristics of fatal infantile hypertonic myofibrillar myopathy (FIHMM).Methods:The clinical manifestations, laboratory assessments data and gene sequencing results of 10 patients diagnosed with FIHMM in Shenzhen Children′s Hospital from February 2017 to April 2021 were retrospectively analyzed.Magnetic resonance imaging (MRI) of both musculoskeletal system and the brain, and electromyogram (EMG) were performed in 3 cases, while muscle biopsy was performed in 2 cases.Results:Among these 10 cases, 1 case was from Northeast China and 1 case from East China, while the rest 8 cases were from South China.Eight of the 10 patients were male, and the other 2 cases were female.They were all born normal and not related to each other.The age of onset varied from 2 to 12 months.The main clinical manifestations for all the patients were progressive rigidity of the rectus abdominis (8 cases), neck muscles (7 cases), rectus abdominis (2 cases) and intercostal muscles (1 case), resulting in respiratory failure.Mildly to moderately elevated serum creatine kinase level was detected (436-5 804 IU/L) (reference range: 24-229 IU/L). Complex repetitive discharges can be seen in the EMG, without any myotonic potential.Muscle fiber degeneration, necrosis, and vacuolar degeneration were noted in the histopathological examination of the vastus lateralis and rectus abdominis.An abnormal red granular deposit was observed in a portion of the field of the modified Gomory Trichrome staining.Immunohistochemistry showed substantial deposition of desmin.Under the electron microscopy, the sarcomere structure of the muscle fibers was seriously disordered, with the destruction of Z-bands and the presence of granular deposits.The whole-exome sequencing identified the same homozygous variation c. 3G>A, p.Met1? of CRYAB gene in all the patients, but heterozygous variation in their parents. Conclusions:Axial muscles involvement, such as rectus abdominis rigidity, is the main clinical characteristic of FIHMM.c.3G>A, p.Met1? mutation in the CRYAB gene is a hotspot mutation in Chinese children.

Aldosterone and renin are important clinical indicators in the diagnosis and treatment of hypertension. There are two kinds of methods for aldosterone detection, including immunoassay and mass spectrometry. The coefficients of variation within the methods, as well as the deviation between methods are large.And the results of immunoassay are much higher than that of mass spectrometry. Clinically, renin tests mainly include renin concentration and renin activity, both of which have advantages and disadvantages in the diagnosis and treatment of hypertension. The disordered test results of aldosterone and renin brings great trouble to the clinical diagnosis and treatment. Standardization/consistency is urgently needed to make the test results of each laboratory more accurate and comparable. The standardization project for renin and aldosterone in China will greatly promote the standardization process in order to provide accurate and comparable clinical tests.

Objective:To evaluate the performance of aldosterone testing in China through the External Quality Assessment (EQA) and improve the testing quality of aldosterone.Methods:Two kinds of EQA program for aldosterone were carried out in China, one of which is Routine EQA and the other is Trueness verification scheme. Lyophilized sera with 5 concentration levels were used as quality control of Routine EQA. The results were grouped according to the instrument. Target values and the coefficient of variation ( CV) were calculated in each group. Trueness verification scheme was verified by using frozen human sera of 3 concentration levels determined by the reference method, and the bias of each instrument group from the target value was calculated. Results:272 laboratories submitted the testing results, and 91.6% of laboratories used chemiluminescence method. The maximum CV was obtained by radioimmunoassay and liquid chromatography mass spectrometry, and the robust CVs were 14.6%-33.4% and 43.5%-53.9%, respectively. For chemiluminescence methods, the robust group CV was less than 10%. The results of the Trueness verification scheme showed that liquid chromatography mass spectrometry method was the most accurate method, with biases of -7.9%, 8.9% and -0.7% for the three quality controls. Diasorin system had the more accurate results deviated from the target by 58.7%, 7.9% and -2.1%, respectively. The results of other chemiluminescence methods were negatively correlated with the sample concentration, and one of them with a bias of 479%. Conclusions:The accuracy and comparability of aldosterone among laboratories in China are not satisfactory. Reagent manufacturers and laboratories should pay more attention to EQA, with the aldosterone results traceable to SI unit, and improve the test quality of aldosterone.

Objective To evaluate the comparability and consistency of two kinds of triglycerides reference methods, one of which is the isotope dilution liquid chromatography-mass spectrometry (LC/MS) in the Cholesterol Reference Method Laboratory Network (CRMLN), the other isthehigh-performance liquid chromatography (HPLC) method for triglyceride detection in China. Methods 52 fresh frozen sera with triglycerides levels among 0.45-4.52 mmol/L were determined by LC/MS and HPLC. After evaluation the precision and accuracy of the two methods,a series of analyses were conducted including plotting to scatter plots and deviation graphs, testing outliers, selecting the best fitting regression models and calculating the regression equations and parameters, and so on. The expected deviation at the level of medical decision of triglycerides and the 95％confidence range were statistically analyzed.Results For HPLC method, the CV of instrument measurement was 0.29％(0％-1.16％), the total CV of samples measurement was 0.54％(0.04％-1.28％), and the average bias of the reference materials was 0.22％(-0.43％-0.68％). ForLC/MSmethod,the CV of instrument measurement was 0.55％(0％-1.68％),the total CV of samples measurement was 0.79％(0％-1.93％), and the average bias of the NIST reference materials was 0.09％(-0.73％-1.29％). No outlier was found from the scatter plots and the statistical analysis and the linear regression was fitted to analyze the results of the two methods. The linear regression parameters of two methods for 52 fresh frozen human sera were as follows:the slope was 0.9988,the standard error of slope was 0.0035, the intercept was 0.0037mmol/L, the standard error of intercept was 0.0030 mmol/L, the standard error of Y-estimate was 0.0236 mmol/L,and the correlation coefficient was 0.9997. Compared with the LC/MS method,the absolute deviation of fresh sera by HPLC method was-0.001 mmol/L (-0.070-0.056 mmol/L), with a relative deviation of 0.13％ (-2.01-2.83％). T-test showed no statistically significant difference between the two methods. The expected deviations at the triglycerides medicine decision level were within the 95％confidence range,and the expected deviations were far less than the allowable error. Conclusions The HPLC method of triglyceridesdetetion has good consistency and comparability with LC/MS method as one of the reference methods of CRMLN. Because of the advantages of HPLC method such as low cost, simplicity,less technical need,and better precision,HPLC method is expected to play an important role in the process of standardization and traceability of serum triglycerides.

Objective To understand the current status of the measurement quality of serum Cystatin C (CysC) in China.Methods The external quality assessment (EQA) data in 2017 were collected from the network platform of National Center for Clinical Laboratories.The EQA data were classified into 8 groups according to different types of diagnostic reagents,each of which was employed by at least 18 users.The robust mean value and robust coefficients of variation (CV) were calculated according to ISO 13528 document in each group.The robust mean value was set as the target value.The total error derived from biological variation was used as the fine (3.8％),moderate (7.6％) and weak (11.4％) criteria in evaluating the pass rates,respectively.The reagents which were employed by more than 50 users were classified into subgroups named as " reagent-analyzer" group according to the used analyzer.The median values and differentials between maximum and minimum value were calculated for each reagent-analyzer subgroup.Results A total number of 710 laboratories submitted their results of CysC measurement during 2017.The fine,moderate and weak pass rates according to the setting criteria were 25.9％ (184/710),55.5 ％ (394/710) and 75.2％ (534/710),respectively.The variations of CysC measurement results of among different reagent-analyzer groups ranged from 1.62％ to 12.27％.Conclusion The quality of CysC measurement of should be improved with nationwide attention.

BACKGROUND:The number of hematopoietic stem cel s in the peripheral blood is very low at normal physiological state. So it is critical to mobilize hematopoietic stem cel s from donor’s bone marrow into the peripheral blood.
OBJECTIVE:To study the combination effect of AMD3100 and dexamethasone on the mobilization of hematopoietic stem cel s in mice, thereby laying the foundation for clinical application.
METHODS:C57BL/6 mice were injected with AMD3100 and dexamethasone alone or in combination. Then, hematopoietic stem cel s in the peripheral blood and bone marrow were col ected. CD34+cel concentration in the peripheral blood and bone marrow was determined by flow cytometer and the content of leucocytes in the peripheral blood was counted by a normal method. The CFU-Mix colony formation ability of hematopoietic stem cel s was identified by cel colony forming assay.
RESULTS AND CONCLUSION:The concentration of CD34+cel s in the peripheral blood and bone marrow, the content of leukocytes in the peripheral blood and the CFU-Mix colony formation ability of hematopoietic stem cel s were al improved by both AMD3100 and dexamethasone and especial y their combined use. This indicates that both AMD3100 and dexamethasone could mobilize hematopoietic stem cel s to migrate from the bone marrow to the peripheral blood, and when used in combination, the mobilization effect is better than that of single drug.

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.

Objective To evaluate the analytical quality of different analytical systems in measuring seven kinds of sero-enzymes consisting of Alanine Aminotransferase(ALT), Aspartate Aminotransferase (AST),γ-Glutamyltransferase(GGT), Lactate Dehydrogenase(LDH), Creatine Kinase(CK), α-Amylase (AMY) and Alkaline Phosphatase(ALP).Methods Data from 2013 routine chemistry external quality assessment (EQA) and Enzymes Trueness Verification(ETV) were collected.1 450 and 165 participating laboratories were selected respectively for investigation.Analytical systems of participating laboratories were classified into 6 kinds,i.e.imported matching system(AI), domestic matching system(AH), systems consisting of imported reagents and corresponding calibrators(BI), systems consisting of domestic reagents and corresponding calibrators ( BH ) , unmatched systems using imported calibrators ( CI ) and unmatched systems using domestic calibrators ( CH ) .Total error, bias and coefficient of variation within laboratories ( CVI) were calculated from the data of 2013EQA and ETV The proportion of laboratories meeting the desirable and the optimal criteria derived from biology variation were analyzedby EXCEL2010 with coincidence rate (CR) above 85% as evaluation criterion.Results The AI and CI occupied more than 70%among six systems, CH occupied approximate 15% and the other systems were less than 10%.The
range of the average of ETV′s total errors , EQA′s total errors, absolute value of bias and CVI of seven kinds of sero-enzymes were 6.2%-27.8%, 4.0%-7.0%, 4.2%-25.1% and 3.6%-4.6% respectively. Accuracy, bias and within-laboratory imprecision were judged by CR of ETV′s total errors, ETV′s bias, CVI and EQA′s total errors respectively and comparability between different systems was evaluated.It turned out that the results of analytical systems of enzymes except ALP were comparable, the accuracy of systems of enzymes except AMY, ALP and GGT, LDH of AI, the within-laboratory imprecision of enzymes except LDH, AMY, ALP and AST of AI, CH could meet the desirable criteria.The bias of all systems of seven kinds of sero-enzymes were undesirable.Conclusions The analytical quality of routine testing of seven kinds of sero-enzymes could fulfill the clinical requirement generally in China.

Objective To evaluate the analytical performance of lipid testing with six sigma(a) in order to promote the quality improvement.Methods Sixty-four Laboratories participated in trueness verification program and Internet-Based Interlaboratory Comparison of Internal Quality Control Data program lipid testing in 2012 were included in this study.The CVs and Bias of TC,TG,HDL-C,and LDL-C for each laboratory were evaluated from the reporting data.The sigma metrics based on the Tea from National Cholesterol Education Program according to the formula:σ =(TEa-Bias)/CV for each analyte.Quality goal index (QGI) was also calculated to investigate the reason for dissatisfied performance as follows:QGI =Bias/ (1.5CV).Results The rates for σ≥6 of TC,TG,HDL-C,and LDL-C were 21.9％,34.4％,9.38％,and 18.8％,respectively.The corresponding rates for 3 ≤ σ ＜ 6 were 31.3％,29.7％,29.7％,and 34.4％,while the rates for σ ＜ 3 were 46.9％,35.9％,60.9％,and 46.9％,severally.For analytes which σ were less than 3,91.3％-100％ of the laboratories should improve the trueness first,0.00％-8.75％ of the laboratories should improve the precision,and 0.00％-2.08％ should improve both.Conclusions Six sigma is an effective tool for quality control in clinical laboratory,which can help improve the quality level for laboratory testing.The analysis of performance of the lipid testing shows that further effort is acquired to enhance the supervision of the trueness verification.