Rapid detection of multidrug-resistant Mycobacterium tuberculosis using the malachite green decolourisation assay

Early detection of drug resistance in Mycobacterium tuberculosis isolates allows for earlier and more effective treatment of patients. The aim of this study was to investigate the performance of the malachite green decolourisation assay (MGDA) in detecting isoniazid (INH) and rifampicin (RIF) resistance in M. tuberculosis clinical isolates. Fifty M. tuberculosis isolates, including 19 multidrug-resistant, eight INH-resistant and 23 INH and RIF-susceptible samples, were tested. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and agreement of the assay for INH were 92.5%, 91.3%, 92.5%, 91.3% and 92%, respectively. Similarly, the sensitivity, specificity, PPV, NPV and agreement of the assay for RIF were 94.7%, 100%, 100%, 96.8% and 98%, respectively. There was a major discrepancy in the tests of two isolates, as they were sensitive to INH by the MGDA test, but resistant by the reference method. There was a minor discrepancy in the tests of two additional isolates, as they were sensitive to INH by the reference method, but resistant by the MGDA test. The drug susceptibility test results were obtained within eight-nine days. In conclusion, the MGDA test is a reliable and accurate method for the rapid detection of INH and RIF resistance compared with the reference method and the MGDA test additionally requires less time to obtain results.     

Conventional Pap smear and liquid-based cytology as screening tools in low-resource settings in Latin America: experience of the Latin American screening study

OBJECTIVE: To evaluate the performance of the conventional Pap test and liquid-based cytology (LBC) in an ongoing multicenter trial testing optional screening tools (cytology, screening colposcopy, visual inspection with acetic acid, visual inspection with Lugol's Iodine, cervicography and Hybrid Capture II [HCII] (Digene Brazil, S?o Paulo, Brazil) conventional and self-sampling), for cervical cancer in Brazil and Argentina. STUDY DESIGN: A cohort of 12,107 women attending four clinics (Campinas, S?o Paulo, Porto Alegre, Buenos Aires) were randomized into the 8 diagnostic arms. Women testing positive with any of the tests were referred for colposcopy, and cervical biopsies were used as the gold standard to assess performance characteristics of the diagnostic tests. Conventional Pap smears were sampled by all clinics (n = 10,240), and LBC (Autocyte PREP, [TriPath Imaging, Burlington, North Carolina, U.S.A.], n=320, and DNA-Citoliq [Digene Brazil], n =1,346) was performed by 1 of the clinics. RESULTS: Conventional Pap smears showed no squamous intraepithelial lesions (normal) in 8,946 (87.4%) and LBC in 1,373 (82.4%). Using high grade squamous intraepithelial lesions (HSIL) as the cutoff, Pap smears predicted high grade (cervical intraepithelial neoplasia [CIN] 3) with OR 63.0 (95% CI, 36.90-107.70), standard error (SE) 59%, SP 97.8%, positive predictive value (PPV) 68.1% and negative predictive value (NPV) 96.7%. The same figures for Autocyte PREP were: OR 9.0 (95% CI, 2.43-33.24), sensitivity (SE) 33.3%, specificity (SP) 100%, PPV 100% and negative PV (NPV) 88.8%. DNA-Citoliq detected CIN 3 as follows: OR 11.8 (95% CI 2.60-53.26), SE 40.0%, SP 94.6%, PPV 40.0% and NPV 94.6%. Lowering the cutoff to low grade squamous intraepithelial lesions increased SE and NPV but compromised SP and PPV. The detection rates for high grade lesions after an atypical squamous cells of undetermined significance diagnosis were similar with the 3 techniques. In our settings, the 3 methods of cervical cytology were slightly different in performance. The conventional Pap smear had the highest SE, while Autocyte PREP had 100% SP and PPV in detecting CIN3 with the HSIL cutoff. All 3 tests had lower SE but higher SP as compared to HCII.     

High prevalence anti-Trypanosoma cruzi antibodies,among blood donors in the State of Puebla,a non-endemic area of Mexico

Blood transfusion is the second most common transmission route of Chagas disease in many Latin American countries. In Mexico, the prevalence of Chagas disease and impact of transfusion of Trypanosoma cruzi-contaminated blood is not clear. We determined the seropositivity to T. cruzi in a representative random sample, of 2,140 blood donors (1,423 men and 647 women, aged 19-65 years), from a non-endemic state of almost 5 millions of inhabitants by the indirect hemagglutination (IHA) and enzyme linked immunosorbent assay (ELISA) tests using one autochthonous antigen from T. cruzi parasites, which were genetically characterized like TBAR/ME/1997/RyC-V1 (T. cruzi I) isolated from a Triatoma barberi specimen collected in the same locality. The seropositivity was up to 8.5% and 9% with IHA and ELISA tests, respectively, and up to 7.7% using both tests in common. We found high seroprevalence in a non-endemic area of Mexico, comparable to endemic countries where the disease occurs, e.g. Brazil (0.7%), Bolivia (13.7%) and Argentina (3.5%). The highest values observed in samples from urban areas, associated to continuous rural emigration and the absence of control in blood donors, suggest unsuspected high risk of transmission of T. cruzi, higher than those reported for infections by blood e.g. hepatitis (0.1%) and AIDS (0.1%) in the same region.     

Development and evaluation of a PCR method for diagnosis of Salmonella enteric fever, based on DNA sequences of the hilA gene

Typically, diagnosis of enteric fever due to Salmonella spp. is by bacterial isolation from blood culture; however, the blood culture method is slow, not always available, and not informative in patients with antibiotic treatment. Salmonella spp. uses the hilA gene (component of the pathogenicity island I) to invade epithelial cells and produce infection. Using the hilA gene sequence a PCR test was designed to detect Salmonella in blood samples. The sensitivity (S), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV) of the PCR method were obtained by testing the blood samples from 34 patients with suspected of enteric fever. Presence of S. typhi was confirmed by blood culture. Blood samples were also tested from 35 patients with infections due to other non-Salmonella pathogens, again corroborated by blood culture (Klebsiella pneumoniae, 9; Serratia marcescens, 5; Escherichia coli, 4; Pseudomonas aeruginosa, 9; Providencia alcalifaciens, 4; Enterobacter cloacae, 4). Control samples were obtained from 150 healthy volunteers. The S, SP, PPV and NPV for the PCR method were all 100%. The lowest number of colony forming units/ml detected by PCR in blood samples was 10.     

Development of a lateral flow test for the rapid detection of <Emphasis Type="Italic">Avibacterium paragallinarum</Emphasis> in chickens suspected of having infectious coryza

Background

Infectious coryza (IC) is an acute respiratory disease of growing chickens and layers caused by Avibacterium paragallinarum. The development of tools that allow rapid pathogen detection is necessary in order to avoid disease dissemination and economic losses in poultry. An Av. paragallinarum-specific Ma-4 epitope of the TonB-dependent transporter (TBDT) was selected using bioinformatic tools in order to immunize a BalbC mouse and to produce monoclonal antibodies to be used in a lateral flow test (LFT) developed for Av. paragallinarum detection in chicken nasal mucus samples.

Results

The 1G7G8 monoclonal antibody was able to detect TBDT in Av. paragallinarum cultures (serogroups: A, B and C) by Western blot and indirect ELISA assay. Consequently, we developed a self-pairing prototype LFT. The limit of detection of the prototype LFT using Av. paragallinarum cultures was 1?×?10⁴ colony-forming units (CFU)/mL. Thirty-five nasal mucus samples from chickens suspected of having infectious coryza were evaluated for the LFT detection capacity and compared with bacterial isolation (B.I) and polymerase chain reaction (PCR). Comparative indicators such as sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive values (NPV) and the kappa index (K) were obtained. The values were 100.0% Se, 50% Sp, 65.4% PPV, 100% NPV, and 0.49?K and 83.9% Se, 100% Sp, 100% PPV, 44.4% NPV, and 0.54?K for the comparison of the LFT with B.I and PCR, respectively. Additionally, the LFT allowed the detection of Av. paragallinarum from coinfection cases of Av. paragallinarum with Gallibacterium anatis.

Conclusions

The results indicate that the self-pairing prototype LFT is suitable for the detection of TBDT in Av. paragallinarum cultures as well as in field samples such as nasal mucus from Av. paragallinarum-infected chickens. Therefore, this prototype LFT could be considered a rapid and promising tool to be used in farm conditions for Av. paragallinarum diagnosis.

     

Detection of Coronavirus 229E Antibody by Indirect Hemagglutination

Tannic-acid treated sheep erythrocytes (fresh or glutaraldehyde preserved) were sensitized with 229E antigens from human embryonic lung (RU-1) cell cultures. Indirect hemagglutination (IHA) antigen titers in 229E-infected cell cultures paralleled virus infectivity and complement fixation (CF) antigen titers. The identity of the IHA antigen was confirmed by testing extracts from inoculated and control cell cultures for ability to inhibit IHA. Also, significant increases in IHA antibody were demonstrated with acute and convalescent serum pairs from patients with proven 229E infections. A comparison of IHA, neutralization and CF titers for 229E antibodies was made on human sera drawn from different populations. The IHA and neutralization results were in agreement on 93% of the 129 sera found to be positive by at least one of three tests. The number of antibody titers detected by the CF test was insufficient to permit comparison. Hyperimmune sera from animals immunized with OC 43 did not react with 229E by IHA. Also no increase in IHA antibody was demonstrated with acute and convalescent serum pairs from patients with seroconversions to OC 43. These findings suggest that the IHA test provides (i) a rapid and sensitive method for serodiagnosis of 229E infections and (ii) a simple and inexpensive method for seroepidemiological studies.     

中耳胆脂瘤的影像诊断:高分辨率计算机断层成像与磁共振成像的比较研究

目的:评估和比较高分辨率计算机断层成像(high resolution computer tomography,HRCT)与磁共振成像(magnetic resonance imaging,MRI)对中耳胆脂瘤的诊断价值。方法:回顾性分析临床初步诊断为中耳胆脂瘤患者55人(63耳)在术前5天内进行的16排HRCT和1.5T MRI诊断结果,以病理诊断为基础对HRCT和MRI的诊断结果进行对比研究,统计分析HRCT和MRI的灵敏度、特异度、阳性预期值、阴性预期值,以及Kappa检验两者之间的内在观察一致性。结果:63耳中,病理确诊为中耳胆脂瘤40耳。HRCT正确诊断30例,假阳性11例,假阴性10例,灵敏度、特异度、阳性预期值以及阴性预期值分别为75%、52.17%、73.17%、54.55%。MRI正确诊断37例,假阳性和假阴性各为3例,灵敏度、特异度、阳性预期值以及阴性预期值分别为92.5%、86.96%、75%和86.96%。HRCT与MRI诊断结果之间的内在观察一致性Kappa=0.274(P0.05)。剔除既往有手术史的10耳,只针对无手术史的53耳,HRCT与MRI诊断结果之间的内在观察一致性增高,吻合度一般,Kappa=0.462(P0.05)。结论:MRI的总体阳性检出率高于HRCT,尤其是对中耳胆脂瘤手术后复发的诊断;HRCT与MRI两者相结合对于中耳胆脂瘤的明确诊断具有互补作用。     

Serodiagnosis of chronic Chagas infection by using EIE-Recombinant-Chagas-Biomanguinhos kit

A kit based on an enzyme immunoassay, EIE-Recombinant-Chagas-Biomanguinhos, developed by the Oswaldo Cruz Foundation, was evaluated for the serodiagnosis of chronic Chagas disease. Evaluation was performed with 368 serum samples collected from individuals living in an endemic area for Chagas disease: 131 patients in the chronic phase with confirmed clinical, epidemiological, and serological diagnosis (indirect immunofluorescence, indirect hemagglutination or enzyme-linked immunosorbent assay) and 237 nonchagasic seronegative individuals were considered negative control. The EIE-Recombinant-Chagas-Biomanguinhos kit showed high sensitivity, 100% (CI 95%: 96.4-100%) and high specificity, 100% (CI 95%: 98-100%). The data obtained were in full agreement with clinical and conventional serology data. In addition, no cross-reaction was observed with sera from patients with cutaneous (n=14) and visceral (n=3) leishmaniasis. However, when these sera were tested by conventional serological assays for Chagas disease, cross-reactions were detected in 14.3% and 33.3% of the patients with cutaneous and visceral leishmaniasis, respectively. No cross-reactions were observed when sera from nonchagasic seronegative patients bearing other infectious disease (syphilis, n=8; HTLV, n=8; HCV, n=7 and HBV, n=12) were tested. In addition, sera of patients with inconclusive results for Chagas disease by conventional serology showed results in agreement with clinical evaluation, when tested by the kit. These results are relevant and indicate that the referred kit provides a safe immunodiagnosis of Chagas disease and could be used in blood bank screening.     

The inclusion of N-terminal pro-brain natriuretic peptide in a sensitive screening strategy for systemic sclerosis-related pulmonary arterial hypertension: a cohort study

Introduction

Pulmonary arterial hypertension (PAH) is a major cause of mortality in systemic sclerosis (SSc). Screening guidelines for PAH recommend multiple investigations, including annual echocardiography, which together have low specificity and may not be cost-effective. We sought to evaluate the predictive accuracy of serum N-terminal pro-brain natriuretic peptide (NT-proBNP) in combination with pulmonary function tests (PFT) (‘proposed’ algorithm) in a screening algorithm for SSc-PAH.

Methods

We evaluated our proposed algorithm (PFT with NT-proBNP) on 49 consecutive SSc patients with suspected pulmonary hypertension undergoing right heart catherisation (RHC). The predictive accuracy of the proposed algorithm was compared with existing screening recommendations, and is presented as sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

Results

Overall, 27 patients were found to have pulmonary hypertension (PH) at RHC, while 22 had no PH. The sensitivity, specificity, PPV and NPV of the proposed algorithm for PAH was 94.1%, 54.5%, 61.5% and 92.3%, respectively; current European Society of Cardiology (ESC)/European Respiratory Society (ERS) guidelines achieved a sensitivity, specificity, PPV and NPV of 94.1%, 31.8%, 51.6% and 87.5%, respectively. In an alternate case scenario analysis, estimating a PAH prevalence of 10%, the proposed algorithm achieved a sensitivity, specificity, PPV and NPV for PAH of 94.1%, 54.5%, 18.7% and 98.8%, respectively.

Conclusions

The combination of NT-proBNP with PFT is a sensitive, yet simple and non-invasive, screening strategy for SSc-PAH. Patients with a positive screening result can be referred for echocardiography, and further confirmatory testing for PAH. In this way, it may be possible to shift the burden of routine screening away from echocardiography. The findings of this study should be confirmed in larger studies.     

Rapid dot sputum and serum assay in pulmonary tuberculosis

A rapid direct sputum (Sp.) and/or antibody assay, based on immunoblotting and enzyme immunoassay is described. The test can detect mycobacterial antigens or antibodies in clinical specimens from pulmonary tuberculosis (TB) patients. In this study, 87 sputa, 87 sera and 40 paired sputa and sera were utilized from smear-positive and smear-negative, culture-positive patients; 59 sputa, 37 sera and 22 paired sputa and sera from nontuberculosis respiratory disease patients and 68 sera from healthy controls. The antigen detection in sputum by dot assay has 86.1% sensitivity on active tuberculosis patients, 92.9% specificity, 91.6% positive predictive value (PPV), 88.2% negative predictive value (NPV) and 10.3% error. The antibody assay has 83.6% sensitivity, 95.4% specificity, 94.4% positive predictive value, 85.6% negative predictive value and 11% error. The test performed on paired sputum and serum (Sr.) samples has a sensitivity of 93.3%, which rose to 96.1% on smear-positive and culture-positive patients, but the specificity decreased to 83% in sputum, whereas in serum it was 92%. The results of the assay, combined with clinical and radiological data, could form the basis for starting an earlier course of treatment for tuberculosis.     

Evaluation of rapid test Assure Helicobacter pylori for diagnosis of H. pylori in pediatric population

Non-invasive tests are needed to assess Helicobacter pylori infection, especially to screen a pediatric population. Assure H. pylori Rapid Test (Genelabs Diagnostics, Singapore) is an immunochromatographic assay device intended for the rapid detection of antibodies to H. pylori in human serum, plasma or whole blood. The aim of this study was to evaluate the performance of the rapid test, Assure H. pylori, in the diagnosis of H. pylori infection in children, using a Portuguese pediatric population. The study group included 130 children with age ranging from 1 to 14 years old (average age 9.2+/-3.1 years). According to the gold standard, 70 of the 130 patients studied were H. pylori positive and 60 were H. pylori negative. Using Assure H. pylori Rapid Test (Genelabs Diagnostics, Singapore), 53 sera had a positive result after 15 min (resulting in 17 false negatives) and 57 sera a negative result (resulting in 3 false positives). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the test were 75.7%, 95.0%, 94.6% and 77.0% respectively. When a longer read time of 45 min is considered, the rapid test revealed a good performance (sensitivity 98.6% and specificity 95%) in the evaluation of the H. pylori infection in a pediatric population. In conclusion, the test showed a good performance, suggesting its applicability as a screening method for the H. pylori infection.     

P16(INK4a) immunocytochemistry in liquid-based cytology samples in equivocal Pap smears: added value in management of women with equivocal Pap smear

OBJECTIVE: To test whether p1l6(INK4a) immunocytochemistry (ICC) in liquid-based cytology (LBC) is useful with colposcopy in abnormal Pap smears. STUDY DESIGN: A series of 248 women with abnormal Pap smear were analyzed for oncogenic (HR) human papillomavirus (HPV) types using the Hybrid Capture II assay and for p16(INK4a) expression using ICC on cervical samples in PreservCyt liquid media. Colposcopic and loop electrosurgical excision procedure (LEEP) cone biopsy were the gold standard. RESULTS: p16(INK4a) ICC did best as predictor of high-grade squamous intraepithelial lesion, with OR 12.18 (2.72-54.57) (p = 0.0001), showing 88.2% sensitivity (SE), 61.9% specificity (SP), 14.6% positive predictive value (PPV) and 98.6% negative predictive value (NPV). In sorting discrepant cases, p16(INK4a) ICC results in 100% SE and 100% NPV in detecting cervical intraepithelial neoplasia (CIN) 2 lesions among Pap+/biopsy- women. In atypical squamous cells undetermined significance (ASCUS) cytology, adding p16(INK4a) ICC improves specificity of colposcopy from 27.3% to 81.8% and PPV from 42.8% to 71.4%. Best performance is obtained with p16(INK4a) ICC and colposcopy: 83.3% SE, 81.8% SP, 71.4% PPV and 90.0% NPV. CONCLUSION p16(INK4a) is useful in sorting clinically relevant discrepant cases, and p16(INK4a) ICC significantly improves SP and PPV of colposcopy in management of ASCUS cytology.     

Predictive power of cytomorphological features in equivocal (C3, C4) breast FNAC

Definitive immediate diagnosis in breast fine needle aspiration cytology (FNAC) remains the aim for cytopathologists. We reviewed 72 consecutive equivocal (C3 and C4) aspirates with respect to 16 cytomorphological criteria. We assessed the power of each criterion at predicting either a malignant [positive predictive value (PPV)] or a benign [negative predictive value (NPV)] diagnosis by correlation with follow-up histology. Blind review led to 34% of cases being correctly definitively diagnosed. Eccentrically placed epithelial cell nuclei (PPV = 88%, sensitivity = 67%, specificity = 87%) and coarse nuclear chromatin (PPV = 81%, sensitivity = 72%, specificity = 83%) are the features that are most useful in predicting malignancy in this selected series. The presence of myoepithelial cells within epithelial groups is not a good indicator of a benign diagnosis (NPV = 24%, sensitivity = 80%, specificity = 53%).     

国产血清半乳甘露聚糖检测试剂对侵袭性肺曲霉菌病的诊断价值评估

目的：评估国产血清半乳甘露聚糖（Galactomannan,GM）检测试剂对侵袭性肺曲霉菌病的诊断价值。方法根据血液病/恶性肿瘤患者侵袭性真菌病的诊断标准与治疗原则（第四次修订版）[1]收集临床确诊侵袭性肺曲霉菌病（inva-sive pulmonary aspergillosis,IPA）、临床诊断IPA、拟诊IPA、排除IPA四组病例。采用天津贻诺琦公司酶联免疫吸附法（ELISA）试剂检测纳入的86例患者血清标本的GM浓度,分析其敏感性、特异性、阳性预测值（PPV）、阴性预测值（NPV）。结果86例病例中,临床诊断27例、拟诊12例、排除47例。在3种不同的阳性判断标准下,敏感性：9444%、9630%、6296%;特异性：5625%、4576%、6441%;PPV：4474%、4483%、4474%;NPV：9643%、9643%、7917%。统计学分析证实标准1（即血清GM值〉095μg/L为阳性,〈075μg/L为阴性,075~095μg/L为灰区,未将灰区加入计算）在3种判断标准中最优,故选择其为最终判断标准。结论该血清GM检测试剂盒诊断性能较好,可以用于侵袭性肺曲霉菌病的辅助诊断。     

The titration of tetanus antitoxin III. A comparative evaluation of indirect haemagglutination and toxin neutralization titres of human sera

The tetanus antitoxin titres of 174 serum samples from healthy adults were determined by a standardization indirect haemagglutination test (IHA) and the conventional toxin neutralization (TN) test. The serum samples were titrated by the IHA test using glutaraldehyde-fixed and toxoid sensitized sheep erythrocytes before and after the treatment of the sera with 2-mercaptoethanol (2-ME). The IHA method has been found to be very sensitive and specific for the estimation of tetanus antitoxin in human sera. The IHA titres before the treatment of the sera with 2-ME were generally about four times higher than the TN titres and the correlation coefficient between these titres was 0.94. The IHA titres after the treatment of the sera with 2-ME were in good agreement with the TN titres and there was no statistically significant differences between the titres by the two methods. The tetanus antitoxin titres of 50% of the sera were below the minimum protective titres of tetanus antitoxin (0.01 IU/ml). In 19.5% of the sera the antitoxin level (IU/ml) ranged from 0.01 to 0.1, in 20.1% from 0.1 to 1.0 and in 10.4% from 1.0 to 10.0.     

Evaluation of Chemotherapy Response with Serum Squamous Cell Carcinoma Antigen Level in Cervical Cancer Patients: A Prospective Cohort Study

MRI does not always reflect tumor response after chemotherapy. Therefore, it is necessary to explore additional parameters to more accurately evaluate tumor response for the subsequent clinical determination about radiotherapy or radical surgery. A training cohort and an external validation cohort were used to examine the predictive performance of SCC-ag to evaluate tumor response from teaching hospital of Harbin Medical University. The study included 397 women with SCC (age: 28–73 years). Patients consecutively enrolled between August 2008 and January 2010 (n = 205) were used as training cohort. Patients consecutively enrolled between February 2010 and May 2011 (n = 192) were used as validation cohort. A multivariate regression analysis of the data from the training cohort indicated that serum SCC-ag level is an independent factor for neo-adjuvant chemotherapy (NACT) response. Analysis of the data from the validation cohort suggested that chemotherapy response could be more accurately predicted by SCC-ag than by magnetic resonance imaging (MRI) (sensitivity (Se): 0.944 vs. 0.794; specificity (Sp): 0.727 vs. 0.636; positive predictive value (PPV): 0.869 vs. 0.806; negative predictive value (NPV): 0.873 vs. 0.618; the area under ROC curve (AUC): 0.898 vs. 0.734). Combining SCC-ag with MRI was more powerful than MRI alone (Se: 0.952 vs. 0.794; Sp: 0.833 vs. 0.636; PPV: 0.916 vs. 0.806; NPV: 0.902 vs. 0.618; AUC: 0.950 vs. 0.734). Our study indicates that serum SCC-ag level is a sensitive and reliable measure to evaluate cervical cancer response to chemotherapy. Using SCC-ag in combination with MRI findings further improves the predictive power.     

Glutaraldehyde fixed-antigen sensitized stable cells in indirect hemagglutination test for rapid diagnosis of hydatid disease, trichinosis and amoebiasis

Glutaraldehyde fixed and antigen sensitized sheep red cells (SRBC) refrigerated or lyophilized in phosphate buffered saline, pH 7·2 (PBS) or in PBS containing 3% normal rabbit serum (PBS-NRS) were stable for more than 6 months in IHA test against sera from patients with hydatid disease, trichinoisis and amoebiasis. The final concentration of protein in hydatid, trichinella and amoebic antigens used for sensitization of SRBC was 0·43, 0·75 and 1·2 mg/ml, respectively. The lyophilized cells in general showed a slightly higher sensitivity but within acceptable limits. By contrast the sensitized cells refrigerated in PBS consistently showed a uniform reactivity and IHA titres were reproducible even 6 months after sensitization of the cells. No demonstrable change was observed in the sensitivity of the test when the PBS-refrigerated cells sensitized 6 months before were exposed to room temperature for 4 days.The following are the main improvements on existing serological tests: (a) a more rapid and reproducible test for sero-epidemiological investigations in areas with minimum laboratory facilities, (b) sensitized cells could be shipped to various laboratories without losing the sensitivity of the test, (c) reduction in the cost of personnel and reagents where these tests are needed infrequently.     

On-levothyroxine measurement of thyroglobulin is not a reliable test for the follow-up of patients at high risk for remnant/recurrent differentiated thyroid carcinoma

INTRODUCTION: At present the most widely accepted tool for follow-up management of differentiated thyroid cancer (DTC) patients is serum thyroglobulin (Tg) measurement. It is not uncommon for the serum Tg level to be measured while the patient is taking thyroid hormones (on-treatment Tg measurement). The purpose of the study was to evaluate the accuracy of on-treatment measurement of serum Tg in detecting remnant/recurrent or metastatic disease in high-risk DTC patients. MATERIAL AND METHODS: We retrospectively analysed the medical records of 26 high-risk DTC patients and compared the on-treatment and off-treatment Tg levels of these patients. All patients were anti-Tg negative. Using off-treatment measurement of Tg as the gold standard, the results of on-treatment measurement of Tg in the diagnosis of remnant/recurrent disease were analysed for sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV). RESULTS: The median serum Tg level under thyroid hormone suppressive therapy (on-treatment Tg) was 16.5 ng/ml and after withdrawal of thyroid hormone suppressive therapy (off-treatment Tg) was 95.0 ng/ml (P value = 0.001). In 6 patients (23%) the on-treatment Tg level missed the recurrence of the disease. Regarding the off-treatment Tg as the gold standard, the sensitivity, specificity, PPV and NPV of the on-treatment Tg measurement were 72.7%, 100%, 100%, and 40% respectively. CONCLUSION: Normal serum Tg level without TSH-stimulation (on-treatment) is not diagnostically reliable in the follow-up of DTC patients with a high probability of residual/recurrent or metastatic disease.     

Commercial enzyme-linked immunosorbent assay versus polymerase chain reaction for the diagnosis of chronic Chagas disease: a systematic review and meta-analysis

Chronic Chagas disease diagnosis relies on laboratory tests due to its clinical characteristics. The aim of this research was to review commercial enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) diagnostic test performance. Performance of commercial ELISA or PCR for the diagnosis of chronic Chagas disease were systematically searched in PubMed, Scopus, Embase, ISI Web, and LILACS through the bibliography from 1980-2014 and by contact with the manufacturers. The risk of bias was assessed with QUADAS-2. Heterogeneity was estimated with the I² statistic. Accuracies provided by the manufacturers usually overestimate the accuracy provided by academia. The risk of bias is high in most tests and in most QUADAS dimensions. Heterogeneity is high in either sensitivity, specificity, or both. The evidence regarding commercial ELISA and ELISA-rec sensitivity and specificity indicates that there is overestimation. The current recommendation to use two simultaneous serological tests can be supported by the risk of bias analysis and the amount of heterogeneity but not by the observed accuracies. The usefulness of PCR tests are debatable and health care providers should not order them on a routine basis. PCR may be used in selected cases due to its potential to detect seronegative subjects.