Evaluation of the Immunoquick+4 malaria rapid diagnostic test in a non-endemic setting

The aim of this retrospective study was to evaluate the Immunoquick+4 (BioSynex, Strasbourg, France), a three-band malaria rapid diagnostic test (MRDT) targeting histidine-rich protein-2 (HRP-2) and pan Plasmodium-specific parasite lactate dehydrogenase, in a non-endemic reference setting. Stored whole-blood samples (n = 613) from international travellers suspected of malaria were used, with microscopy corrected by polymerase chain reaction (PCR) as the reference method. Samples infected by P. falciparum (n = 323), P. vivax (n = 97), P. ovale (n = 73) and P. malariae (n = 25) were selected, as well as 95 malaria-negative samples. The overall sensitivities of the Immunoquick+4 for the diagnosis of P. falciparum, P. vivax, P. malariae and P. ovale were 88.9, 75.3, 56.0 and 19.2%, respectively. Sensitivity was significantly related to parasite density for P. falciparum (93.6% versus 71.4% at parasite densities >100/μl and ≤100/μl, respectively) and P. vivax (86.8% versus 48.3% at parasite densities >500/μl and ≤500/μl, respectively). The Immunoquick+4 showed good reproducibility and reliability for both test results and line intensities. The Immunoquick+4 performed well for the detection of P. falciparum and P. vivax.     

Neuropsychologists' abilities to determine the predictive value of diagnostic tests.

The diagnostic utility of a test is relative to the base rate of the diagnosis in the population of interest. The extensive use of tests in neuropsychological assessment makes knowledge of the relevance of base rates in this context an important issue. Professional and associate members of the National Academy of Neuropsychology (NAN; n=279) answered questions involving (1) a simple use of base rates in the absence of additional diagnostic information, (2) sensitivity and specificity, and (3) positive predictive value (PPV) presented in either a probability or frequency format. Although the majority of participants answered correctly the simple base rate, sensitivity, and specificity questions, only 8.6% answered correctly the PPV question presented in a probability format versus 63.0% correct using a frequency format. These results are discussed in terms of education about the importance and application of base rate information and difficulties applying base rate information in practice.     

Clinical and laboratory profile of trichinellosis from a non-endemic country

Trichinellosis is a zoonotic parasitic infection caused by nematodes of the genus Trichinella. Humans mostly get infected by eating raw/under-cooked pork. In India, it has been reported mostly as sporadic cases especially from North Eastern and Eastern part of country.In this study, we retrospectively analyzed the socio-demographic pattern, clinical presentation, laboratory profile and treatment response in Trichinella-infected patients visiting our tertiary care center which mainly caters to patients from North India. For this retrospective laboratory-based analysis, patients diagnosed on the basis of positive anti-Trichinella IgG antibodies between 1^st June 2008, and 31^st May 2019 were included.A total of 11 positive trichinellosis cases were detected, of whom majority were children who presented with history of fever, gastrointestinal symptoms, myalgia, eosinophilia along with hepatomegaly and pulmonary manifestations. No CNS involvement was seen in any of the patients although it is commonly associated with Trichinella infection. All patients recovered uneventfully after antihelminthic treatment.     

Significance and value of the Widal test in the diagnosis of typhoid fever in an endemic area.

The diagnostic value of the Widal test was assessed in an endemic area. The test was done on 300 normal individuals, 297 non-typhoidal fevers and 275 bacteriologically proven cases of typhoid. Of 300 normal individuals, 2% had an H agglutinin titre of 1/160 and 5% had an O agglutinin titre of 1/160. On the basis of these criteria a significant H and/or O agglutinin titre of 1/320 or more was observed in 93-97% of typhoid cases and in only 3% of patients with non-typhoidal fever. Of the sera from typhoid cases which gave a significant Widal reaction, the majority (79.9%) showed increases in both H and O agglutinins and 51 of 234 (21.8%) of these sera were collected in the first week of illness. The significance and implications of these findings are discussed.     

Trypanosoma cruzi infection in a non-endemic country: epidemiological and clinical profile

Chagas disease has been increasingly diagnosed in non-endemic countries. This is a prospective observational study performed at the Tropical Medicine Units of the International Health Program of the Catalan Health Institute, Barcelona (PROgrama de Salud Internacional del Instituto Catalán de la Salud, PROSICS Barcelona, Spain), that includes all patients with Chagas disease who attended from June 2007 to May 2012. Clinical and epidemiological data were collected. Overall, 1274 patients were included, the mean age of the patients was 37.7 years, 67.5% were women and 97% came from Bolivia. Thirteen patients had immunosuppressive conditions. The prevalence of cardiac involvement was 16.9%, lower than in previous studies performed in endemic areas (20–60%). Cardiac alterations were found in 33.8% of symptomatic and 14.1% of asymptomatic patients. The prevalence of digestive involvement was 14.8%. The rate of digestive involvement is very different among previous studies because of different diagnostic tools and strategies used. Barium enema alterations were found in 21.4% of symptomatic and 10.3% of asymptomatic patients, and oesophageal alterations were found in 3.7% of symptomatic and in 2.3% of asymptomatic patients. As shown in previous studies, Chagas disease in non-endemic countries affects younger patients and has lower morbidity.     

Widal test in diagnosis of typhoid fever in Turkey

We studied the value of the Widal tube agglutination test for the diagnosis of typhoid fever. The subjects were all adults >18 years of age and were divided into four groups: (i) 317 healthy blood donor controls, (ii) 31 bacteriologically confirmed patients with Salmonella enterica serotype Typhi, (iii) 21 patients with a clinical diagnosis of typhoid fever, and (iv) 41 febrile nontyphoid patients. Blood donor controls were screened with a slide agglutination test for the Salmonella enterica serotype Typhi O and H antigens, and positives were then tested with the Widal test. Acute- and convalescent-phase sera from patients in groups 2, 3, and 4 were obtained 7 to 10 days apart and tested by the Widal test. Using a cutoff of >or = 1/200 for the O antigen test performed on acute-phase serum gave a sensitivity of 52% and a specificity of 88% with a positive predictive value (PPV) of 76% and a negative predictive value (NPV) of 71%. This increased to 90% sensitivity and specificity with a PPV of 88% and an NPV of 93% when the convalescent-phase serum was tested. We concluded that O and H agglutinin titers of > or = 1/200 are of diagnostic significance. The Widal test is easy, inexpensive, and relatively noninvasive. It can be of diagnostic value when blood cultures are not available or practical. The results must be interpreted cautiously because of the low sensitivity of the test. The Widal test done on convalescent-phase serum gave more-reliable results with higher specificity and sensitivity.     

Retrospective study on the diagnostic value of IgG ELISA, dot immunoassay and indirect hemagglutination in septicemic melioidosis.

Three serological methods for diagnosis of melioidosis were compared with the culture method currently used as the "gold standard". The diagnostic values of the serological methods were evaluated retrospectively in 306 patients residing in an endemic area. The enzyme-linked immunosorbent assay (ELISA), using affinity purified antigen for detecting specific IgG antibody, showed a slightly higher specificity (86.0%) than the dot immunoassay (DOT) (84.0%) and both were superior to indirect hemagglutination (IHA) (72.0%). The sensitivity of DOT (96.4%) and ELISA (85.7%) were considerably higher than that of IHA (50.0%). The primary benefit of the high negative predictive value of both ELISA (96.4%) and DOT (99.0%) in an area of high prevalence is the ability to rule out most of the non-melioidosis patients.     

Seroprevalence and asymptomatic carriage of Leishmania spp. in Austria,a non-endemic European country

Leishmaniasis is a rare disease in Central Europe and is diagnosed almost exclusively in travellers or migrants coming from tropical or subtropical countries. We conducted an explorative cross-sectional serological study, using a commercial ELISA, in 1048 healthy Austrian individuals to assess the distribution of specific antibodies against Leishmania spp. in humans in Austria. Overall, 47 individuals (4.5%) tested positive, and an additional 32 (3.1%) showed borderline results. After 12 months, sera from 42 of the 79 individuals who had initially tested seropositive/borderline were tested by ELISA a second time: 18 were persistently positive, nine were borderline. Those whose sera were persistently positive/borderline were then screened for potential carrier status using a commercial oligochromatographic PCR test to detect parasite DNA. Four samples were PCR positive and were subjected to a second PCR allowing parasite identification after DNA sequencing: two samples were identified as Leishmania donovani/infantum complex and Leishmania (Viannia) guyanensis, respectively. Epidemiological information was obtained with a questionnaire: no correlation was found for the number of holiday trips within the previous 6 months, but a significant risk of exposure to Leishmania spp. was found for travel to the New World, particularly to the Caribbean. Our data demonstrate that Leishmania spp. seroprevalence in non-endemic countries has been considerably underestimated.     

Retrospective analysis of the diagnostic and therapeutic value of video-mediastinoscopy for disease of mediastinum

为了探讨电视纵隔镜对纵隔淋巴结肿大及纵隔疾病的诊断和治疗价值,对20例电视纵隔镜手术检查患者的临床资料进行回顾性分析.20例患者均获得病理诊断,其中结节病8例,结核2例,小细胞肺癌2例,胸腺囊肿2例,肉芽肿性炎1例,淋巴结增生1例,肺腺癌1例,纵隔囊肿1例,胸腺癌1例,霍奇金淋巴瘤1例.出血1例,无手术死亡及其他并发症发生.初步研究结果提示,电视纵隔镜对纵隔淋巴结肿大及纵隔疾病的诊断和治疗安全准确.     

Study of the diagnostic value of the dexamethasone suppression test in endogenous depression

The diagnostic value of the dexamethasone suppression test (DST) in "endogenous" depression was evaluated in 209 psychiatric inpatients. A high incidence of abnormal DST results was observed in "endogenous" depressives (52%), schizo-affective (69%) and borderline patients (38%). However, 25% of the patients with other psychiatric disease also failed to suppress on the DST. Diagnostic criteria, previous history of alcoholism, psychiatric drug treatment, age and sex did not significantly affect DST performance. The present data do not indicate that the DST represents a highly specific marker of "endogenous" depression.     

Comparative diagnostic performance of two commercial rapid tests for malaria in a non-endemic area

In the study reported here, the diagnostic performance of two new rapid tests for the diagnosis of malaria was evaluated in symptomatic patients in a non-endemic area. Of 557 consecutive patients, 109 (19.6%) had documented malaria. For the NOW ICT MALARIA P.f./P.v. (Binax, Portland, ME, USA) and OptiMAL IT (Diamed, Cressier, Switzerland) tests, respectively, sensitivity values were 96.3% and 79.8% (P-value, 0.0001), and specificity values were 98.8% and 98.4%. The NOW ICT test did not detect two of 80 Plasmodium falciparum infections, and it generated false-positive results for five patients. The OptiMAL IT test failed to detect ten of the P. falciparum infections, and it generated seven false-positive results. The results suggest that these rapid diagnostic tests for malaria may be useful, but they cannot replace microscopic examination of blood films.     

How to: evaluate a diagnostic test

Background

The development of an in vitro diagnostic test from a good idea to a clinically relevant tool takes several steps, with more stringent requirements at every step.