Auramine-O Staining vs Ziehl Neelsen Staining: Advantages and Disadvantages

Background: Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) is still a major public health concern around the world. Prompt detection of active tuberculosis cases helps in timely therapeutic intervention and reduces community transmission. Despite limited sensitivity, conventional microscopy is still used to diagnose pulmonary tuberculosis in high-burden nations such as India. This study, therefore, was aimed at assessing the diagnostic performance of microscopy by Ziehl Neelsen (ZN) and auramine (AO) staining in the diagnosis of pulmonary tuberculosis. Materials and methods: A prospective comparative study was done on the sputum samples of 2,395 adult patients from November 2018 to May 2020 suspected of having pulmonary tuberculosis visiting the Designated Microscopic Centre of SGT Medical College, Budhera, Gurugram. Each sample was subjected to ZN staining, and AO staining as per NTEP guidelines. Results: Out of the 2,395 samples studied, 161 (6.76%) and 224 (9.35%) were positive by ZN and AO staining methods respectively. Pauci-bacillary cases detected by AO were more than ZN staining. There were 63 more sputum samples detected by AO staining which were missed by ZN microscopy. Conclusion: When compared to conventional ZN staining, the auramine staining technique is more sensitive and takes less time to diagnose pulmonary tuberculosis

Strike Omicron before you Captures It !

Omicron is currently shaking the world to its core. The disease is mainly transmitted via the respiratory route when people inhale droplets and small airborne particles (that form an aerosol) that infected people exhale as they breathe, talk, cough, sneeze, or sing. “UK becomes first country in Europe to pass 1,50,000 COVID deaths Omicron clouds forecasts for Covid end game.Omicron is a variant of nSARS-CoV-2 that has been identified initially in COVID19 patients in Botswana and South Africa. The chief of the World Health Organization (WHO), Tedros Adhanom Ghebreyesus, has said that the combination of Delta and Omicron variants of coronavirus is driving a tsunami of COVID-19 cases. The statement came as record new cases were reported from the United States and countries across Europe. France recorded the highest ever daily numbers in Europe for the second consecutive day, at 208,000 new cases.Vaccines offer strong protection from serious illness.

Role of CBNAAT in the Diagnosis of Extra-Pulmonary Tuberculosis: Experience from a Tertiary Care Hospital in India

Background. Xpert-MTB/RIF assay or Cartridge-Based Nucleic Acid Amplification Test (CBNAAT) helps in rapid diagnosis of tuberculosis (TB). Methods. Specific samples were collected and carried to Regional Medical Research Centre where these were taken up for CBNAAT and culture in Lowenstein-Jensen media. Appropriate samples were sent to the Designated Microscopy Centre (DMC) of our institute for acid-fast bacilli (AFB) smear examination. Diagnostic measures, such as sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of Xpert-MTB/RIF were reported considering mycobacterial culture and a composite reference standard (CRS) as Gold standard. Results. We studied 335 samples. Lymph node fine needle aspirate was the most common sample (32.5%) followed by pleural fluid (29.3%). The overall sensitivity and specificity of Xpert-MTB/RIF was determined to be 26.5% (95% CI [confidence interval] 20.8�.8) and 100% (95% CI 96.8�0), respectively. The sensitivity and specificity of CBNAAT in relation to mycobacterial culture, however, was 78.8% (95% CI 61.1�.0) and 89.1% (95% CI 85�.4), respectively. Both were highest for pus, cerebrospinal fluid and lymph node fine needle aspirate samples. Conclusions. Xpert-MTB/RIF may be useful for samples, like cold abscess and lymph node fine needle aspirate or biopsy specimens. However, its routine use in case of serosal fluids is not recommended because of its lower sensitivity.

Expert consensus on nucleic acid amplification test of respiratory pathogens in children / 中华实用儿科临床杂志

Acute respiratory tract infection is the most common infectious disease in children, which seriously threatens children′s health.Rapid and accurate etiological diagnosis is of great significance for the clinical treatment and control of these diseases.Pathogen nucleic acid test was applied and became the main method of respiratory tract infection diagnosis for its high sensitivity and specificity.To regulate the application of pathogen nucleic acid amplification test in respiratory tract infection in children, improve the diagnosis level, expert consensus on nucleic acid amplification test of respiratory pathogens in children was prepared to guide the application and promote pathogens diagnosis ability.

Seizures in a child with tuberculomas: case report

Central tuberculomas, occurring because of the haematogenous spread of' M. tuberculosis, can present variably with the symptoms ranging from headache, decreased level of consciousness, neck stiffness to altered mental status, seizures and focal deficits. Diagnostic investigations include but are not limited to CSF analysis, MRI Brain, CT head, and AFB smear, mycobacterial cultures or CBNAAT of the CSF sample. Magnetic resonance spectroscopy can help distinguishing the tuberculoma from its differentials by showing a peculiar lipid peak. Treatment with the antituberculosis drugs over a prolonged period of time along with dexamethasone usually shows significant clinical improvement. Authors present to you the case report of an 8 year old boy who presented to the pediatric emergency with generalized tonic clonic seizures and was subsequently detected with the tuberculoma with the help of MRI Brain and CBNAAT (cartridge based nucleic acid amplification test) of CSF sample. The objective of this case report is to discuss the symptoms, pathogenesis, detection and management of tuberculomas, which are still quite common in the developing countries and if left untreated are associated with high morbidity and mortality.

Comparative Study of Conventional Ziehl Neelsen and Modified Bleach Method of Ziehl Neelsen with CBNAAT in the Diagnosis of Tuberculous Lymphadenitis

Tuberculosis is one of the major health problems in developing countries like India. Even though lungs are the commonly involved organs in Tuberculosis, extrapulmonary presentations are on the rise nowadays. Among the various types of presentations of extrapulmonary tuberculosis, lymphadenitis is the most common presentation. A spectrum of investigations is available for diagnosis, and molecular methods like CBNAAT and PCR analysis are highly reliable. But their disadvantage is their cost and requirement of trained personnel. FNA is the first line of investigation but is lacking in sensitivity and culture method is time consuming. So, Modified Ziehl Neelsen method with low cost and less time may be considered as an alternative. We wanted to evaluate the sensitivity of the Modified Bleach Ziehl Neelsen method and compare the Modified and Conventional Ziehl Neelsen Method in association with the CBNAAT in the diagnosis of TB lymphadenitis.METHODSDiagnostic validation study was conducted with 30 clinically suspected cases of tuberculosis. FNA was done and aspirated material was spread on 2 slides. Slides were stained with H & E stain and convention Ziehl Neelsen stain. Part of the aspirate material was centrifuged with 5 % sodium hypochlorite. Sediment was smeared on a slide and stained with Ziehl Neelsen stain. Remaining material was subjected to CBNAAT assay.RESULTSCorrelation shows that 9, 6, and 11 out of 30 cases were positive for tuberculosis in Conventional, Modified and CBNAAT methods respectively. Sensitivity was 81.81 %; specificity was 94.74%, positive predictive value was 90% and negative predictive value was 90% for Conventional Ziehl Neelsen Method and 54.55%, 94.73%, 85.71% and 78.26%, respectively for modified bleach method.CONCLUSIONSConventional method is found to be more sensitive than modified method. CBNAAT negative results do not rule out TB. So, they should be correlated with cytology and microbiological studies.

A prospective study of outcome in infertility patients diagnosed with genital tuberculosis

Background: Tuberculosis is an increasing health problem worldwide with around 9.6 billion new cases reported every year. Female genital tuberculosis (FGTB) has a varying incidence ranging from a very low of 0.69% in developed nations to as high as 19% in developing nations like India. The average incidence of infertility due to tuberculosis is 5-10% worldwide.Methods: The study was a hospital based prospective clinical study, from September 2014-2017 with sample size of 355 infertility cases. Endometrial sampling and diagnostic hystero-laparoscopy were used for diagnosis. Endometrial sample subjected for both the test CBNAAT and HPR was used for confirmation of positive patients. Inclusion criteria were, infertile patients diagnosed with genital tuberculosis who were then given treatment. Patients diagnosed to have infertility due to causes other than TB were excluded from the study. Highly suspected cases and those who were willing underwent diagnostic laparoscopy.Results: Out of 355 cases of infertility, 83 were because of genital TB, received treatment out of which 32 conceived.  CBNAAT was very sensitive than histopathology or laparoscopy. The live birth rate and conception rate were 20.24% and 38.09 % respectively.Conclusions: CBNAAT is OPD based economical test (free by GOI), very sensitive and picked up more cases than histopathology or laparoscopy. The live birth rate and conception rate were found to be higher than other studies possible due to intervention at an earlier stage of the disease process. This test should be widely used by gynecologist for early detection of genital tuberculosis.

Diagnostic yield of cartridge based nucleic acid amplification test in Mycobacterium tuberculosis in a tertiary care medical college and hospital of Southern Odisha, India

Background: Tuberculosis is the ninth leading cause of death worldwide. India contributes to about one fifth of global TB burden. It is very important to diagnose early and treat tuberculosis to cut down transmission of tuberculosis.Methods: Author conducted a retrospective study in Department of Pulmonary Medicine SLN Medical College, Koraput, Odisha to analyze the utility and yield of CBNAAT. Study period was from April 2018 to March 2019. Inclusion criteria was all patients whose samples were subjected to CBNAAT were included in our study.  Sputum samples from pulmonary tuberculosis patients, and extra pulmonary samples (pleural fluid, ascitic fluid, CSF, synovial fluid and gastric lavage etc. were included in our study population. Exclusion criteria was patients who were under anti tubercular therapy for pulmonary, extra pulmonary and MDR TB were excluded from this study. Data were collected from Pulmonary Medicine Department, ART center, DOTS center and CBNAAT center. Total number of samples tested for CBNAAT, different sample collection sites, age and sex distribution of patients, HIV status of all patients, result of smear microscopy for AFB and CBNAAT and Rifampicin resistance status were analyzed.The detail statistical analysis was done in tabulation form.Results: A total of 2621 samples were tested in CBNAAT during the study period. Mean age of the study population was 38.03 years. 1881 tested were negative and 740 samples were positive for CBNAAT. Of these 2621 samples, 2526 were pulmonary samples (sputum, pleural fluid samples) and 95 were extra pulmonary samples. Author found rifampicin resistance rate of 0.54% (4/740)) in pulmonary tuberculosis cases. There was no rifampicin resistance detected in extra pulmonary samples. CBNAAT could identify 536 cases (23.2%) that were smear negative. Author found TB- HIV co-infection rate of 6.22%.Conclusions: CBNAAT is an important diagnostic modality especially in sputum negative patients for early diagnosis and treatment. In our study it detected Mycobacterium tuberculosis in 23.2% of patients with negative smear for microscopy. Rifampicin resistance rate detected was very low compared to other studies.

Role of cartridge-based nucleic acid amplification test to diagnose tuberculosis at tertiary care teaching hospital in Rajasthan, India

Background: Tuberculosis is one of the top 10 causes of death worldwide as per the Global TB report 2017, the estimated incidence of TB in India was approximately 28,00,000 cases accounting for about a quarter of the world’s TB cases (10 million). It is of utmost important to diagnose early and treat it to reduce disease transmission. GeneXpert MTB/RIF, an automated cartridge-based molecular technique detects Mycobacterium Tuberculosis and rifampicin resistance within two hours, has been recommended by WHO for rapid diagnosis of TB.Methods: Author conducted a retrospective study in the Department of TB and Chest, of tertiary care center at Jhalawar Medical College (JMC), Jhalawar to evaluate and analyze the role of CBNAAT to diagnose tuberculosis from 1st January 2018 to 31st December 2018. Author included all patients who came to department of TB and Chest of JMC, Jhalawar either new/ relapsed/ defaulters/ referred cases from ART/ ICTC center, Pediatric Department; Gynaecology and Obstetrics Department, peripheral Government Health Care Facilities and Private Hospitals of Jhalawar District catering about 15.5 lac population were subjected to both ZN staining/ Fluorescent microscopy and CBNAAT in the study period.Results: A total of 3078 samples (pulmonary 2739+EP 339) were tested for ZN staining / Fluorescent microscopy and CBNAAT during the study period. Mean age of the study population was 36.5±10.3 years. 1873 tested were negative and 1205 samples were positive for CBNAAT. Of these 1205 positive samples, 1174 were sputum/ BAL samples and 31 were extra pulmonary samples. Authors found rifampicin resistance rate of 6.98% (82/1174) in pulmonary tuberculosis cases, 3 rifampicin resistance cases were detected in extra pulmonary samples. CBNAAT could identify 255 cases (14.01%) that were smear negative. Author found TB-HIV coinfection rate of 18.75%.Conclusions: Author found CBNAAT to be an important diagnostic modality especially in smear negative patients for early diagnosis and treatment. Author could detect Mycobacterium Tuberculosis in 14.01% of patients with negative smear microscopy for AFB. In PLHIV, CBNAAT detected Mycobacterium Tuberculosis in 18.75% (12/64) of patients. Author found rifampicin resistance rate of 6.98% (82/1174) in pulmonary tuberculosis cases.

Utility of cartridge based nucleic acid amplification test in the diagnosis of extra pulmonary tuberculosis

Background: Tuberculosis is one of the top 10 cause of death globally. Extra-pulmonary tuberculosis is an important clinical problem. Extra-pulmonary tuberculosis range from 30%-53% in India. Diagnosis of extra-pulmonary tuberculosis is still challenging despite many investigations. World Health Organization recommends Gene-Xpert Mycobacterium Tuberculosis/Rifampicin (Cartridge Based Nucleic Acid Amplification Test-CBNAAT) over conventional tests for diagnosis of extra-pulmonary tuberculosis which permits rapid tuberculosis diagnosis through detection of the genetic sequence of DNA of mycobacterium tuberculosis and simultaneous identification of a majority of the mutations that confirm Rifampicin resistance which is highly predictive of multi-drug resistant tuberculosis.Methods: Study was carried out over a period of one year. Patients with suggestive of extra-pulmonary tuberculosis were included in study. Diagnosis of extra-pulmonary tuberculosis carried out by clinical, radiological, biochemical analysis, cytological, bacteriological confirmation. Based on mycobacterium tuberculosis result, the study population were divided into ‘Mycobacterium Tuberculosis detected’ and ‘Mycobacterium Tuberculosis not detected’ groups. Mycobacterium Tuberculosis detected group was further divided into ‘Rifampicin resistant’ and ‘Rifampicin sensitive’.Results: Total 220 patients were included. Among extra-pulmonary tuberculosis, there were 83.64% were pleural fluid. 65.91% patients where be <45 years of age. Mostly patients were from rural areas and illiterate. Diabetes Mellitus found as the most common co-morbidities. CB-NAAT was able to detect mycobacterium tuberculosis in 35% (77) extra-pulmonary samples, out of which 6 were rifampicin resistant. Out of 184 samples of pleural fluid, 53 were rifampicin sensitive and 4 were found rifampicin resistant.Conclusions: CB-NAAT has to be endorsed in every health care centres as the test gives rapid result and also detection of rifampicin resistance which is the major concern for every clinician.

Pattern of tuberculosis among tribal population of Central India with special reference to cartridge based nucleic acid amplification test as diagnostic tool: a descriptive study at tertiary care hospital

Background: Tuberculosis (TB) kills close to half a million Indians every year. Lack of reliable rapid diagnostic techniques for TB hampers timely diagnosis and leads to continued disease transmission, causing significant morbidity and mortality. The potential of newly recommended CBNAAT in TB and MDR-TB detection has been underutilized in our area due to lack of awareness regarding the same. Hence we utilized this rapid, logistically simplified test to study the pattern of tuberculosis among tribal population of Central India.Methods: Descriptive study of suspected TB patients in tertiary care centre from March 2016 to March 2019. Appropriate specimens from suspected TB patients were collected and subjected to CBNAAT and AFB smear to study the pattern of TB and Rifampicin- Resistant(RR) TB  in our area.Results: CBNAAT detected overall 27% MTB cases; 27.72 % Pulmonary-TB cases as against smear positivity rate of 20.73% whereas 12.74% Extra-pulmonary-TB (EPTB) cases as against smear positivity rate of 1.59%.Overall 94.91% were RiF Sensitive( RS-TB) and 4.58% were RR-TB. Of the 57 (4.16%) HIV-TB coinfected cases; 96.49% were RS-TB and 5.26% were RR-TB. Co-infected patients have high incidence of EPTB(21.05%) involvement  with RR-TB 3.50%. Among EPTB cases; lymph node aspirate and pus provided highest CBNAAT positive cases and almost 90.62% EPTB specimens were RS-TB .Conclusions: Availability of new diagnostic services has increased early identification of TB and RR-TB. Awareness among physicians regarding diagnostic utility of CBNAAT should be further increased as early identification of possible MDR cases is key to reducing community transmission and treatment initiation, particularly in high-burden, resource-limited settings.

Diagnosis of pulmonary tuberculosis with cartridge based nucleic acid amplification test and light emitting diode fluorescent microscopy: a comparative study

Background: Due to low sensitivity and inability to detect drug resistance, smear microscopy limits its impact on TB control. Culture methods and drug susceptibility testing is complex, time consuming, and takes around 6-8 weeks. A new diagnostic test, cartridge based nucleic acid amplification test (CBNAAT) was developed based on real-time polymerase chain reaction (RT PCR). Objective of this study to compare the results of CBNAAT for diagnosis of pulmonary tuberculosis with LED fluorescent microscopy and sputum culture.Methods: A cross-sectional study was conducted in the department of Chest and TB, CIMS, Bilaspur. Each Sputum sample of presumptive TB patients were tested with CBNAAT, sputum smear microscopy by light emitting diode (LED) fluorescent microscopy (FM) and solid and liquid culture for diagnosis of Tuberculosis. Results of CBNAAT, Fluorescent Microscopy and Culture for detection of Mycobacterium Tuberculosis were compared.Results: The sensitivity and specificity for CBNAAT were 97% and 100% respectively; while that for Fluorescent microscopy were 70% and 100% respectively. The positive and negative predictive value for CBNAAT was 100% and 96% respectively. The positive and negative predictive value for Fluorescent microscopy was 100% and 73% respectively.Conclusion: CBNAAT is having high sensitivity and specificity for diagnosis of pulmonary tuberculosis. It should be routinely used under national health programme to detect a tuberculosis case efficiently.

Diagnosis of paediatric tuberculosis by cartridge based nucleic acid amplification test and its effectiveness as compared to the other conventional diagnostic methods

Background: Childhood TB constitutes 10-20% of all TB cases in high burden countries like India and accounting for 8-20% of TB related deaths. Diagnosis of TB in children is difficult. One test, CBNAAT which was recently endorsed by WHO has the potential to lead a revolution in diagnosis of active TB disease.Methods: A cross sectional study in SCB MCH and SVPPGIP, Cuttack in all the suspected TB patients admitted during the period from January 2016 to October 2017.Results: A total of 100 suspicious patients admitted to the Department of Pediatrics in SCB MCH and SVPPGIP during the study period. Of these 45 were diagnosed TB and rest others were diagnosed otherwise than TB. Diagnosis of TB was established on basis of Microscopy, CBNAAT, culture, biochemistry, cytology, clinical findings, neuroimaging, FNAC/biopsy, USG abdomen. Out of 45 TB patients 30 were CBNAAT positive taking the body fluid samples other than blood, urine and stool with a sensitivity of 66.7% and specificity of 100%. Out of 45 TB patients 14 were having ZN Smear positive taking the same fluid sample with a sensitivity of 31.1% and specificity of 100%. Whereas out of these 45 TB patients 32 were MGIT culture positive taking the same sample with a sensitivity of 71.1% and specificity of 100%. When diagnostic performances of CBNAAT and MGIT culture were compared, it was found to be statistically insignificant with a P value 0.54.Conclusions: The CBNAAT is able to confirm a diagnosis of TB with 66.7% sensitivity and 100% specificity within 2 hours. We can use CBNAAT as a diagnostic method as it provides rapid result and simultaneous better sensitive result, it can be helpful in starting ATT in sick patients and also in outdoor patients.

Investigation of the Association of HCV or HIV Markers in Non-Discriminated Blood Donations / 대한수혈학회지

HBV core antibody and surface antibody test are currently conducted for those donors showing non-discriminated reactive (NDR) results on a nucleic acid amplification test (NAT) as a blood donor screening assay. It is necessary to investigate the relationship with HCV or HIV in the donors showing NDR results. From June 12th, 2012 to December 31st, 2018, 0.05% (9,020/17,798,461) donors showed NDR results on a NAT. Among the donors showing NDR results, 17 and 18 donors showed positive results on serological assay of HCV and HIV, respectively. 23 donors with NDR results showed positive results on the serological assay or NAT for HCV or HIV on the following donation. Further study and more accumulated data are required because it may be difficult to find the cause of NDR results by the current serological assay that is used for screening blood donors.

Laboratory Diagnosis of Clostridium difficile Infection in Korea: The First National Survey

In May 2015, we conducted a voluntary online survey on laboratory diagnostic assays for Clostridium difficile infection (CDI) across clinical microbiology laboratories in Korea. Responses were obtained from 66 laboratories, including 61 hospitals and five commercial laboratories. Among them, nine laboratories reported having not conducted CDI assays. The toxin AB enzyme immunoassay (toxin AB EIA), nucleic acid amplification test (NAAT), and C. difficile culture, alone or in combination with other assays, were used in 51 (89.5%), 37 (64.9%), and 37 (64.9%) of the remaining 57 laboratories, respectively, and 23 (40.4%) of the laboratories performed all three assays. Only one laboratory used the glutamate dehydrogenase assay. Nine laboratories used the toxin AB EIA as a stand-alone assay. The median (range) of examined specimens in one month for the toxin AB EIA, NAAT, and C. difficile culture was 160 (50–2,060), 70 (7–720), and 130 (9–750), respectively. These findings serve as valuable basic data regarding the current status of laboratory diagnosis of CDI in Korea, offering guidance for improved implementation.

A study on early detection of pulmonary tuberculosis in smear negative retroviral positive patients by using CBNAAT

Background: Tuberculosis is one of the most common opportunistic infections among people with HIV infection. Detection of pulmonary tuberculosis by sputum-based techniques includes microscopy and culture. However, in people living with HIV, sputum production is scanty and also the sputum contains less number of bacilli due to fewer cavitations, thereby decreasing the sensitivity and specificity of sputum microscopy as a diagnostic tool. Aim of the study: In this study, we assess the usefulness of CBNAAT in the early detection of pulmonary tuberculosis and its incidence by using CBNAAT in smear-negative HIV patients using mycobacterial culture in Lowenstein Jensen medium as Gold Standard. Materials and methods: The study was conducted in the Department of Cardiothoracic Surgery, Government Mohan Kumaramangalam Medical College Hospital. Data were collected from 150 HIV infected patients who tested sputum smear negative. Sputum samples were then sent for CBNAAT and sputum culture for mycobacteria. Results: Of the 150 patients enrolled, 28(18.66%) of them were detected with MTB by CBNAAT; whereas sputum culture could detect 38(25.33%) of them. Thus, compared to sputum smear, CBNAAT increases TB detection by 18.66% and sputum culture increases by 25.33%. The sensitivity of CBNAAT in our study was 73.68% and the incidence of smear-negative pulmonary TB in the study population by using CBNAAT was 18.66%. Conclusion: CBNAAT is a highly sensitive and diagnostic stool for the diagnosis of pulmonary TB and it is of immense help in the early diagnosis of smear-negative pulmonary TB in HIV infected patients. Therefore, CBNAAT should be used as the initial test in HIV infected patients suspected with pulmonary TB.

Incidence, epidemiology and control of Clostridium difficile infection in a tertiary care private hospital in India

Purpose: Clostridium difficile infection (CDI) is a serious healthcare-associated infection (HAI) now being increasingly reported from hospitals across India. However, there is a paucity of data on the incidence of and impact of control measures on CDI in India. Materials and Methods: This is a retrospective study conducted at a tertiary care hospital in Mumbai from January 2016 to December 2017. All patients with healthcare-onset diarrhoea were tested for C. difficile by glutamate dehydrogenase (GDH)/toxin assay or nucleic acid amplification test (NAAT). CDI was defined as either GDH and toxin positive or NAAT positive. The incidence of CDI was calculated per 1000 patient days. Demographic features of patients with CDI including age, sex, duration of hospitalisation before onset of CDI, antibiotic use and treatment administered were summarised. Results: A total of 67 patients had CDI in the study period with a mean incidence of 0.2/1000 patient days. A halving of the CDI incidence was seen after intensification of the CDI prevention bundle. The mean age of affected patients was 64 years and CDI occurred at a median duration of 2 weeks after hospitalisation. Eighty-seven per cent of the patients were on antibiotics at the time of diagnosis of CDI. The crude mortality rate was 22%. Conclusions: CDI is an emerging HAI in India. All hospitals need to set up policies for surveillance, testing, treatment and prevention of CDI based on recent international guidelines and local infrastructure/logistics.

The Role of the Signal-to-Cutoff Ratio in Automated Anti-HCV Chemiluminescent Immunoassays by Referring to the Nucleic Acid Amplification Test and the Recombinant Immunoblot Assay

BACKGROUND: Following discontinuation of the recombinant immunoblot assay (RIBA), the only available supplementary test for the detection of hepatitis C virus (HCV) is the nucleic acid amplification test (NAAT). However, the NAAT does not adequately detect past HCV. Consequently, it is hard to distinguish between past HCV infection and biological false positivity with an anti-HCV result alone. We assessed the diagnostic performance of two immunoassays: the ARCHITECT anti-HCV chemiluminescent microparticle immunoassay (CMIA; Abbott Diagnostics, Wiesbaden, Germany) and the Access HCV Ab PLUS chemiluminescent immunoassay (CIA; Bio-Rad, Marnes-la-Coquette, France). We also explored an optimized algorithm to determine the anti-HCV results. METHODS: We tested 126,919 patients and 44,556 individuals who underwent a medical checkup. RIBA and NAAT were conducted for samples that tested anti-HCV-positive using CMIA and CIA. We assessed the optimal signal-to-cutoff (S/CO) ratio in HCV-positive samples. RESULTS: In total, 1,035 blood samples tested anti-HCV-positive. Of these, RIBA was positive in 512, indeterminate in 160, and negative in 363 samples. One hundred sixty-five samples were NAAT-positive. Diagnostic sensitivity and positive predictive value (PPV) were 96.7% and 52.1%, respectively, for CMIA, and 94.7% and 72.3%, respectively, for CIA. The optimal S/CO ratio was 5.2 for CMIA and 2.6 for CIA at 95% PPV. In total, 286 samples tested positive in CMIA and 444 in CIA, while 443 samples tested positive in both assays. CONCLUSIONS: It is hard to determine anti-HCV positivity based on the S/CO ratio alone. However, this study elucidated the role of the S/CO ratio by using the NAAT and RIBA.

Effect analysis of improving the HIV positive detection rate by single sample nucleic acid amplification test in Shenzhen / 国际检验医学杂志

Objective To investigate the effect of improving the human immunodeficiency virus (HIV)posi-tive detection rate by single sample nucleic acid amplification test (SS-NAT) in Shenzhen ,and to explore the effect of SS-NAT on reducing the risk of HIV infection in transfusion .Methods 269 228 blood samples were performed parallel detection by SS-NAT (Procleix Tigris ) and two kinds of enzyme-linked immuno sorbent assay(ELISA)reagents ,and then the samples with nonreactive by ELISA and reactive by SS-NAT were tested by HIV identification assay .The blood donors with reactive HIV identification assay were made tracing tests . All the samples with reactive by ELISA or HIV identification assay were sent to the Shenzhen Center for Dis-ease Control and Prevention (CDC) for Western Blot (WB) diagnostic tests .Results The samples with reac-tive by the third generation ELISA reagents ,the fourth generation ELISA reagents ,both ELISA reagents and SS-NAT were 188 ,340 ,422 and 103 ,which reactive rate was 0 .698‰(188/269 228) ,1 .263‰(340/269 228) , 1 .567‰(422/269 228) and 0 .383‰(103/269 228) ,respectively .We found four samples with nonreactive by ELISA but reactive by SS-NAT .The four donors were found HIV reactive by both ELISA and SS-NAT after tracing .All the samples with reactive by ELISA or HIV identification assay were sent to CDC for confirmatory tests and 103 of them were positive .The positive detection rate of transfusion-transmissible HIV infection af-ter ELISA detection was 1∶67 307(4/269 228) .Conclusion The application of SS-NAT in blood screening can improve the HIV positive detection rate ,shorten window period of HIV detection and reduce residual risk of transfusion-transmissible HIV infection ,and then blood safety can be effectively improved .

Cytomegalovirus Infection under a Hybrid Strategy in Pediatric Liver Transplantation: A Single-Center Experience / 대한소아소화기영양학회지

PURPOSE: To evaluate the outcomes of a hybrid prophylactic strategy to prevent cytomegalovirus (CMV) disease in pediatric liver transplantation (LT) patients. METHODS: CMV DNAemia was regularly monitored by quantitative nucleic acid amplification test (QNAT) and was quantified in all children. CMV infection and disease were defined according to the International Consensus Guidelines. The hybrid strategy against CMV infection consisted of universal 3-week prophylaxis and preemptive treatment of intravenous ganciclovir regardless of the recipient's serostatus. RESULTS: A total of 143 children who underwent living donor LT were managed using the hybrid strategy. The overall incidence of CMV infection by QNAT was 48.3% (n=69/143). The highest CMV DNAemia positivity was observed in 49.2% (n=60/122) of children in the D+/R+ group, followed by 46.7% (n=7/15) in the D+/R− group. CMV disease was noted in 26.1% (n=18/69) patients. Forty-three (62.3%) children had undergone preemptive therapy consisting of intravenous ganciclovir. No symptomatic patients developed tissue-invasive disease, resulting in no CMV-associated mortality. CONCLUSION: The incidence of CMV infection was high in pediatric LT patients despite the hybrid strategy. However, tissue-invasive disease in pediatric LT did not occur.