Objective To investigate the interference effect of nitrite on the determination of 24 h urine total protein by pyrogallol red method and evaluate the feasibility of using vitamin C to correct this interference.Methods According to the CLSI EP7-A3 document,fresh urine specimens with 24 h urine total protein concentrations of 150 mg/L,500 mg/L and 1 000 mg/L were selected as control samples,and interfering samples containing different concentrations of sodium nitrite were prepared.The interference of nitrite was con-firmed through paired difference experiments,and the relationship between nitrite concentration and interference level was clarified u-sing dose-effect experiments.The effects of different concentrations of vitamin C on correcting the interference caused by 200 μg/mL so-dium nitrite were evaluated.Additionally,61 nitrite-positive and 40 nitrite-negative clinical specimens were collected to compare the relative differences before and after vitamin C correction to assess its clinical application value.Results In the paired difference exper-iments,200 μg/mL sodium nitrite had relative interferences of-157.8％and-36.2％on the determination of urine total protein of 150 mg/L and 500 mg/L respectively,which were significantly greater than 1/2TEa(22％).Although there was a-20.5％negative interference for the high concentration of 1 000 mg/L urine total protein,the interference was within the acceptable range.The dose-effect experiment results showed that as the nitrite concentration in urine increased,the negative interference on urine total protein de-tection also gradually increased.In the presence of 200 μg/mL sodium nitrite as the final concentration,the addition of 0.2 mg/mL vi-tamin C corrected the urine total protein at 150 mg/L and 500 mg/L to 148 mg/L(-1.1％)and 402 mg/L(-19.5％),respectively,both within the acceptable range.The relative differences produced by vitamin C correction in the nitrite-positive clinical specimen group were significantly higher than those in the nitrite-negative group(P＜0.01).Conclusions Nitrite produced negative interference on the determination of urine total protein by the pyrogallol red method,especially when the urine total protein is 150 mg/L,which needs attention of clinical laboratories.The addition of 0.2 mg/mL vitamin C could effectively correct the interference of nitrite in low-concentration of urine total protein specimens,showing potential clinical application value.

Objective To establish and evaluate a rapid detection method for SARS-CoV-2 based on reverse transcriptase-recombinase aided amplification(RT-RAA)combined with the clustered regularly interspaced short palindromic repeats(CRISPR)/Cas12a system.Methods RT-RAA primers and CRISPR-derived RNA(crRNA)were designed based on the nucleocapsid(N)gene of SARS-CoV-2 from NCBI database.The detection system was optimized with magnesium acetate(MgAc)concentration,RT-RAA reaction tempera-ture and time and LbCas12a reaction temperature.The sensitivity and specificity of the method were evaluated using recombinant plas-mids(100-106 copies/μL)and other respiratory pathogens.The RT-RAA-CRISPR/Cas12a method was compared with RT-PCR by tes-ting 70 clinical samples in parallel.Results The optimized RT-RAA-CRISPR/Cas12a assay could detect SARS-CoV-2 within 50 min at 37 ℃.The limit of detection was 10 copies/μL for the fluorescence-based method and 1×102 copies/μL for the lateral flow assay.The method specifically detected SARS-CoV-2 without cross-reactivity to other respiratory pathogens.The results of testing 70 clinical samples using RT-RAA-CRISPR/Cas12a showed agreement of 100％with those of RT-PCR.Conclusion The established RT-RAA-CRISPR/Cas12a assay for SARS-CoV-2 detection is rapid,cost-effective,highly sensitive and specific.It can be performed by less experienced personnel and no expensive equipment is required,thus it may provide a new approach for rapid clinical diagnosis and large-scale on-site screening of SARS-CoV-2.

Objective To establish an intelligent detection algorithm model for acute promyelocytic leukemia(M3 model)based on a contrast large model using machine learning statistical software and validate its effectiveness.Methods The data from 8 256 outpa-tients and inpatients who underwent complete blood cell analysis at Peking Union Medical College Hospital were retrieved and analyzed using the laboratory information system(LIS)and hospital information system(HIS).A M3 screening model was established and vali-dated using the data from outpatients and inpatients who underwent complete blood cell analysis at our hospital from July to October 2023.Results The M3 model demonstrated potential application value in screening for M3 disease in complete blood cell analysis,which showed certain efficacy in screening for neutrophil toxicity changes,particularly in identifying two cases of blue-green inclusion bodies in neutrophils.Conclusion The M3 model exhibited low specificity for M3 diagnosis.Future research should focus on increas-ing the number of M3-positive cases to optimize the model,ensuring high sensitivity while improving specificity.This model will provide assistance for the intelligent review of complete blood cell analysis.

Objective To explore the relationship between the triglyceride-glucose(TyG)index,residual cholesterol(RC)and dia-betic nephropathy(T2DM).Methods A total of 410 patients with T2DM were consecutively selected from the Endocrinology Depart-ment of Jiangsu Provincial Traditional Chinese Medicine Hospital from March 2022 to March 2023.The patients were stratified into three groups based on their morning urinary albumin-to-creatinine ratio(UACR):269 patients were in simple diabetes mellitus(SDM)group,80 in early diabetic nephropathy(EDN)group and 61 in clinical diabetic nephropathy(CDN)group.Comparative an-alyses were conducted on the three groups in terms of gender,age,past medical history,body mass index(BMI),systolic blood pres-sure(SBP),diastolic blood pressure(DBP),fasting blood glucose(FBG),Urea,creatinine(Cr),urinary albumin(UA)total cholesterol(TC),triglycerides(TG),high-density lipoprotein cholesterol(HDL-C),and low-density lipoprotein cholesterol(LDL-C).Additionally,TyG index and RC were calculated.Spearman analysis was employed to evaluate the correlation between UACR and these various parameters.Binary Logistic regression was utilized to identify independent risk factors for diabetic nephropathy(DN).The diagnostic performances of Urea,Cr,TyG index and RC for type 2 diabetic nephropathy were assessed using receiver operating charac-teristic(ROC)curve analyses.Results Compared with SDM group,diabetes duration,SBP,Urea,UA,TG,TC,TyG index and RC showed significant increases in EDN group with statistically significant differences(P＜0.05),and diabetes duration,SBP,DBP,Urea,Cr,UA,TG,TC,LDL-C,TyG index and RC in CDN group also exhibited significant increases,with statistically significant differences(P＜0.05).Spearman rank correlation analysis revealed a positive correlation between RC and UACR(r=0.278,P＜0.001),a positive correlation between TyG index and UACR(r=0.239,P＜0.001)and a positive correlation between RC and TyG in-dex(r=0.562,P＜0.001).Binary logistic regression analysis showed that diabetes duration,SBP,Urea,Cr,TyG index(OR=2.815,95％CI:1.481-5.349,P=0.002),and RC(OR=2.179,95％CI:1.038-4.574,P=0.04)were independent risk factors for DN.The area under the ROC curve(AUCROC)for RC predicting DN occurrence was 0.670(95％CI:0.616-0.725),while the AUCROC for the TyG index was 0.620(95％CI:0.564-0.676).Conclusion TyG index and RC were significantly correlated with the development of DN in the patients with T2DM,which may early facilitate clinical identification and management for the patients in the risk ofr diabetic kidney disease.

Objective To isolate E.scherichia coli-specific bacteriophages from hospital waste water,analyze their biological character-istics and detect their cleavage effects on bacterial biofilms.Methods The phages were isolated and purified by double-layer agar plate method and their morphology was observed by transmission electron microscopy.Their one-step growth curve,in vitro lysis curve,tem-perature and acid-base stability were determined.Whole genome sequencing was used to analyze the genome composition and character-istics of bacteriophages.The crystal violet staining was used to evaluate the scavenging effects of phage on host biofilms.Results A novel Escherichia coli-specific bacteriophage named vB_EcoP-R1 was isolated from hospital sewage.Transmission electron microscopy revealed that the morphology of vB_EcoP-R1 was similar to that of Podoviridae,a member of Caudovirales,and it could survive stably in the temperature range of-20 ℃ to 50 ℃ and pH 5.0 to 11.0.The total length of the vB_EcoP-R1 genome was 40 875 bp and the GC content was 49.94％.There were no virulence genes and drug resistance genes in the phage genome.vB_EcoP-R1 was capable of lysing clinically isolated Escherichia coli and showed high species and genus specificity.After the phage acted on the host bacteria preformed biofilm for 4 h,the clearance rate of the biofilm reached 80.16％.Conclusion vB_EcoP-R1 should be a novel Escherichia coli-specif-ic bacteriophage with strong lysis and high specificity for species and genus.The bacteriophage could lyse the biofilm formed by the host bacteria,and is expected to be used as an alternative treatment for Escherichia coli infection.

Objective To analyze the distribution and drug resistance patterns of carbapenem-resistant Acinetobacter baumannii(CRAB),and evaluate the antimicrobial effects in vitro of colistin(COL)combined with cefoperazone/sulbactam(SCF),tigecycline(TGC),imipenem(IPM),meropenem(MEM),amikacin(AK),and levofloxacin(LEV)against CRAB to provide guidance for anti-infective therapy.Methods A total of 75 non-duplicate CRAB strains isolated from clinical specimens in 2022 were collected.WHONET 5.6 software was used for retrospective analysis of their clinical distribution and resistance profiles.Among them,25 strains were selected for combined antimicrobial susceptibility tests using broth microdilution to determine minimum inhibitory concentrations(MICs).The fractional inhibitory concentration(FIC)index was calculated based on checkerboard method to assess the combined effects.Results In 2022,a total of 145 Acinetobacter baumannii strains were isolated,including 75 CRAB(detection rate of 51.7％).CRAB was most prevalent in the patients over 70 years old(40.0％),mainly from blood(41.3％)and sputum(37.3％)specimens,and the intensive care unit was the top isolating department.All the 75 CRAB strains were resistant to piperacillin,piperacillin/tazobactam,ceftriaxone,1PM and MEM with resistance rates of 100％.The resistance rates for ampicillin/sulbactam,cefepime and tri-methoprim/sulfamethoxazole were all exceeded 95％.The resistance rates were 86.7％for LEV,82.7％for SCF,77.4％for AK,2.4％for TGC,and 0.0％for COL.The results of combined tests of 25 strains revealed the synergy rates of 92％and 80％for COL+SCF and COL+TGC respectively with sums of both synergy and additive rates of 100％.Synergy rates for COL combined with IPM,MEM,AK and LEV were 64％,72％,56％and 48％respectively.No antagonism was observed in any combination.Conclusion The drug resist-ance of CRAB exhibited high levels at our hospital,and the elderly and ICU patients were the major susceptible populations.Among all the combinations tests,COL+SCF showed optimal synergy while COL+LEV only had the lowest combined effect with the findings that warrants clinical consideration.

Objective To investigate the diagnostic value of immunophenotype in distinguishing acute promyelocytic leukemia(APL)from HLA-DR negative acute myeloid leukemia(AML)using flow cytometry.Methods A retrospective observational study was con-ducted including 42 APL patients and 28 newly diagnosed or relapsed HLA-DR negative AML patients admitted to our hospital from 2014 to 2024.Immunophenotype analysis was performed on bone marrow aspirate samples using flow cytometry.The positive expression rates of CD64,MPO,CD7,CD11c,CD9,CD123 and other antigens were compared between the two groups using the Chi-square test.The diagnostic efficiency of the CD9/123 and CD64+MPO+CD7 CD11c-models for APL was evaluated using receiver operating charac-teristic(ROC)curves.Results The HLA-DR negative AML group exhibited significantly lower positive rates of CD64,CD9 and MPO(P＜0.05),and higher positive rates of CD11c and CD7(P＜0.05)compared to APL group.The CD64+MPO+CD7-CD11c-model had an area under the curve(AUCROC)of 0.859,sensitivity of 93.8％and specificity of 75.0％for distinguishing APL.The CD9/CD123 expression pattern had AUCROC of 0.919,sensitivity of 83.3％and specificity of 84.0％for APL diagnosis.The combined CD9/123 and CD64+MPO+CD7-CD11c-model had AUCROC of 0.955,sensitivity of 83.3％and specificity of 100％.Conclusion The combined CD9/123 and CD64+MPO+CD7-CD11c-expression pattern may serve as a helpful tool for differentiating APL from HLA-DR negative AML.

Objective To analyze the prevalent characteristics,sequence type(ST),and blaOXA gene distribution of global Acineto-bacter pittii,and provide reference for prevention and clinical medication against this infection.Methods All the sequences of A.pittii genomes were downloaded in batch from NCBI by using Aspera software with deadline of November 30,2023,and perl script was used to extract the meta information of strains in batch from the downloaded GBK file.A self-made Perl program was utilized to extract the nucleotide coding sequence of the gene from each genome sequence file of A.pittii as the analysis database.BLASTN comparative analy-sis was implemented by using the allelic sequences of 7 housekeeping genes of the genus Acinetobacter Sp downloaded from the website as a query database to determine the ST of each genome.The nucleotide sequences of the blaOXA genes were downloaded from the NCBI pathogen resistance gene database and the self-written AMRG software was utilized to analyze the distribution of blaOXA gene among A.pittii.Results A total of 305 A.pittii genomes were obtained,which were mainly isolated from 1990 to 2020.The isolation rates showed an increasing trend of year by year with the highest isolation rate in 2015.The separation rates of the United States,China and Germany ranked in the top three positions,with the separation rates of 29.5％(90 strains),15.7％(48 strains),and 13.4％(41 strains),respectively.A total of 180(59.0％)specimens were sourced from humans,of which 42(23.3％)were from sputum,27(15.0％)from blood,and 15(8.3％)from skin and soft tissues.The 305 strains of A.pittii were assigned into 79 STs,among which ST93(14.4％),ST64(12.1％)and ST63(11.8％)accounted for the highest proportion.In the United States,China and Germany,the infections were mainly affected by ST64,ST63 and ST93,respectively.The 305 A.pitti carried the blaOXA gene except 6 strains,while the remained 299 strains carried 31 blaOXA variants,of which,252 blaOXA genes were found to own the carbapenemase hydrolysis activity and 146 strains carried blaOXA-500 gene.Conclusion There should be regional differences in the global distribution of A.pittii,and the high prevalence of the carbapenemase gene blaOXA suggested a potential trend of multi-drug resistance,which is worthy to be monitored.

Objective To analyze nonconformities between 2012 and 2022 version of ISO 15189,and provide strategies of transitioning to new standard for laboratories.Methods A total of 522 nonconformities from 32 on-site audits in 24 laboratories against ISO 15189:2012 were collected and mapped them to the relevant clauses of ISO 15189:2022.Strategies for transitioning ISO 15189 to new version were explored based on the standard requirements,literature review and current laboratory practices.Results On average,16 noncon-formities(range from 8 to 31)were identified in every on-site audit.Most of them were related to ISO 15189:2022 clauses 7.3 Exami-nation Processes(165 nonconformities).The others were clause 6.5 Equipment Calibration and Metrological Traceability(43)and clause 6.6 Reagents and Consumables(40).Relatively fewer nonconformities involved new/enhanced requirements,such as risk man-agement,patient-related processes and point-of-care testing.Conclusion The main nonconformities in ISO 15189:2022 predominantly involved in the link of examination processes.It should be suggested that the laboratories strengthen the management in this area by a-dopting digital/intelligent technologies in order to smoothly implement the requirements of the new version of ISO 15189:2022 standard.A comprehensive strategy,including incorporating training,gap analysis,document revision,implementation involved in all staff,stringent risk management and continuous improvement should be recommended to ensure successful transition progress for replacement of ISO 15189:2022.

Objective To apply PDCA(plan,do,check and action)cycle to optimize management and shorten the turnaround time(TAT)of five sex hormone tests for improving clinical efficiency and patient satisfaction.Methods A PDCA management team was established to retrospectively analyze the current status of sex hormone TAT in 2021.In 2022,PDCA tools were utilized,including fishbone diagrams for cause analysis,Pareto charts for root cause identification,formulation and implementation of corresponding im-provement measures and monitoring of TAT changes before and after PDCA.Results Through the corrective measures,such as staff personnel training,increasing testing equipment,optimization process and other improvement measures,the median TAT of sex hor-mone samples in 2022(post-PDCA improvement)was 54 minutes which was significantly lower than 61 minutes in 2021(pre-PDCA)(P＜0.05).Conclusion PDCA cycle management effectively shortened the TAT of sex hormone samples,enhanced clinical diagnostic efficiency and patient experience,improved doctor-patient relationships,while also elevated the quality management standards of labo-ratories.