scholarly journals Defective particles of human T-lymphotropic virus and negative results in molecular assays

2021 ◽  
pp. 105141
Author(s):  
Adele Caterino-de-Araujo ◽  
Karoline Rodrigues Campos
Keyword(s):  
T Lymphotropic Virus ◽  
Molecular Assays ◽  
Negative Results

scholarly journals HTLV-1 AND TUBERCULOSIS ASSOCIATION: A REVIEW OF THE LITERATURE

2014 ◽  
Vol 2 (2) ◽  
Author(s):  
Normeide Pedreira dos Santos ◽  
Monique Lírio ◽  
Rita Elizabeth Moreira Mascarenhas ◽  
Leonardo Pereira Santana ◽  
Bernardo Galvão Castro ◽  
...  
Keyword(s):  
Cochrane Library ◽  
T Lymphotropic Virus ◽  
Negative Results ◽  
Size Number ◽  
Group Response ◽  
Increased Risk ◽  
The Relationship

Objective: To review and evaluate the scientific evidences on the relationship between tuberculosis (TB) and HTLV-1 infection. Methods: Searches on MEDLINE, LILACS/SciELO and Cochrane Library databases were performed using the following keywords: HTLV-1 Infection, Human T-lymphotropic virus type 1; Paraparesis Tropical Spastic; Tuberculosis. The following data were evaluated: Study design, sample size, number of controls, frequency of HTLV-1 infection in patients with TB and uninfected controls, mortality in HTLV-1/TB coinfected individuals compared with controls group, response in vivo and in vitro to PPD, frequency of individuals with tuberculin skin test (TST) positive or negative. Results: Nineteen articles were selected: twelve investigated prevalence, four mortality, three evaluated both prevalence and mortality and six described immunological findings. The majority of the studies was conducted in South America (Brazil and Peru), and Japan. Seven out of 12 studies found an increased risk of HTLV-1 in patients with TB diagnosis. The prevalence of HTLV-1/TB co-infection ranged from1.49 % in Brazil to 11.4 % in patients in Peru. Two out of five studies found a higher mortality of patients with HTLV-1/TB co-infection compared to patients with TB alone. Three studies conducted in Africa (Guinea Bissau and Senegal) found no increase in the mortality of patients co-infected with TB and HTLV-1. A decreased response to PPD in vitro or in vivo was observed in co-infected individuals compared with patients with TB alone. Conclusion: Patients with TB diagnosis have a higher prevalence of HTLV-1, compared with uninfected controls. Co-infection HTLV-1/TB increases the mortality of TB.

scholarly journals Clinical Performance of SARS-CoV-2 Molecular Tests

2020 ◽  
Vol 58 (8) ◽  
Author(s):  
Daniel A. Green ◽  
Jason Zucker ◽  
Lars F. Westblade ◽  
Susan Whittier ◽  
Hanna Rennert ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Severe Disease ◽  
False Negative ◽  
Patient Specific ◽  
Molecular Testing ◽  
Repeat Testing ◽  
Initial Testing ◽  
Molecular Assays ◽  
Negative Results ◽  
Positive Results

ABSTRACT Molecular testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the gold standard for diagnosis of coronavirus disease 2019 (COVID-19), but the clinical performance of these tests is still poorly understood, particularly with regard to disease course, patient-specific factors, and viral shedding. From 10 March to 1 May 2020, NewYork-Presbyterian laboratories performed 27,377 SARS-CoV-2 molecular assays from 22,338 patients. Repeat testing was performed for 3,432 patients, of which 2,413 had initial negative and 802 had initial positive results. Repeat-tested patients were more likely to have severe disease and low viral loads. The negative predictive value of the first-day result among repeat-tested patients was 81.3% The clinical sensitivity of SARS-CoV-2 molecular assays was estimated between 58% and 96%, depending on the unknown number of false-negative results in single-tested patients. Conversion to negative was unlikely to occur before 15 to 20 days after initial testing or 20 to 30 days after the onset of symptoms, with 50% conversion occurring at 28 days after initial testing. Conversion from first-day negative to positive results increased linearly with each day of testing, reaching 25% probability in 20 days. Sixty patients fluctuated between positive and negative results over several weeks, suggesting that caution is needed when single-test results are acted upon. In summary, our study provides estimates of the clinical performance of SARS-CoV-2 molecular assays and suggests time frames for appropriate repeat testing, namely, 15 to 20 days after a positive test and the same day or next 2 days after a negative test for patients with high suspicion for COVID-19.

scholarly journals Clinical Performance of SARS-CoV-2 Molecular Testing

2020 ◽  
Author(s):  
Daniel A. Green ◽  
Jason Zucker ◽  
Lars F. Westblade ◽  
Susan Whittier ◽  
Hanna Rennert ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Severe Disease ◽  
False Negative ◽  
Molecular Testing ◽  
Repeat Testing ◽  
Clinical Sensitivity ◽  
Initial Testing ◽  
Molecular Assays ◽  
Negative Results ◽  
False Negative Results

AbstractMolecular testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the gold standard for diagnosis of coronavirus disease 2019 (COVID-19), but the test clinical performance is poorly understood. From 3/10/2020-5/1/2020 NewYork-Presbyterian laboratories performed 27,377 SARS-CoV-2 molecular assays from 22,338 patients. Repeat testing was performed in 3,432 patients, of which 2,413 had negative and 1,019 had positive first day results. Repeat-tested patients were more likely to be older, male, African-American or Hispanic, and to have severe disease. Among the patients with initially negative results, 18.6% became positive upon repeat-testing. Only 58.1% of any-time positive patients had a result of “detected” on the first test. The clinical sensitivity of COVID-19 molecular assays is estimated between 66.2 % and 95.6%, depending on the unknown number of false negative results in single-tested patients. Conversion to a negative result is unlikely to occur before 15 to 20 days after initial testing or 20-30 days after the onset of symptoms, with 50% conversion occurring at 28 days after initial testing. Forty-nine initially-positive patients converted to negative and then back to positive in subsequent days. Conversion from first day negative to positive results increased linearly with each day of testing, reaching 25% probability in 20 days. In summary, our study provides estimates of the clinical performance of SARS-CoV-2 molecular assays and suggests time frames for appropriate repeat testing, namely 15 to 20 days after a positive test and the same or next 2 days after a negative test in a patient with high suspicion for COVID-19.

scholarly journals Difficulties in the diagnosis of HTLV-2 infection in HIV/AIDS patients from Brazil: comparative performances of serologic and molecular assays, and detection of HTLV-2b subtype

2007 ◽  
Vol 49 (4) ◽  
pp. 225-230 ◽  
Author(s):  
Helena Kaminami Morimoto ◽  
Arilson Akira Morimoto ◽  
Edna Maria Vissoci Reiche ◽  
Luiz Toshio Ueda ◽  
Tiemi Matsuo ◽  
...  
Keyword(s):  
Virus Type ◽  
Restriction Analysis ◽  
Serum Samples ◽  
Aids Patients ◽  
Specific Antibodies ◽  
T Lymphotropic Virus ◽  
Molecular Assays ◽  
Pcr Products ◽  
Hiv Aids

The current diagnosis of human T-lymphotropic virus type-2 (HTLV-2) infection is based on the search of specific antibodies; nevertheless, several studies conducted in Brazil pointed deficiencies of the commercially available kits in detecting HTLV-2, mostly in HIV/AIDS patients. This study searched for the presence of HTLV-1 and -2 in 758 HIV/AIDS patients from Londrina, Paraná, Brazil. Serum samples were screened for HTLV-1/2 antibodies using two EIA kits (Vironostika and Murex), and confirmed by WB (HTLV Blot 2.4, Genelabs). The results obtained by EIA disclosed 49 (6.5%) reactive sera: 43 positive by both EIA kits, and six with discordant results. WB confirmed HTLV-1 infection in seven samples (0.9%) and HTLV-2 in 21 sera (2.8%). Negative and indeterminate results were detected in four (0.5%) and 16 (2.1%) sera, respectively. Blood from 47 out of 49 HTLV seroreactive patients were collected and analyzed for the presence of env, LTR and tax genomic segments of HTLVs by PCR. PCR confirmed six cases of HTLV-1 and 37 cases of HTLV-2 infection (14 out of 16 that were found to be WB indeterminate). Restriction analysis of the env PCR products of HTLV-2 disclosed 36 isolates of HTLV-2a/c subtype, and one of HTLV-2b subtype. These results emphasize the need of improving serologic tests for detecting truly HTLV-2 infected patients from Brazil, and confirm the presence of HTLV-2b subtype in the South of this country.

scholarly journals Antibody to human T-lymphotropic virus in a patient with Guillain-Barré syndrome (case report)

1991 ◽  
Vol 33 (4) ◽  
pp. 329-331 ◽  
Author(s):  
C.M. Nakauchi ◽  
A.C. Linhares ◽  
M.L.C. Gomes ◽  
K. Maruyama ◽  
L.I. Kanzaki ◽  
...  
Keyword(s):  
Guillain Barre Syndrome ◽  
Enzyme Linked Immunosorbent Assay ◽  
Epstein Barr Virus Infection ◽  
Serum Samples ◽  
T Lymphotropic Virus ◽  
Adult T Cell Leukemia ◽  
Barr Virus ◽  
Negative Results ◽  
Guillain Barré Syndrome ◽  
Guillain Barré

Serum sample obtained from a male, 12 year old patient suffering from Guillain-Barré syndrome (GBS) was positive for human T-lymphotropic virus (HTLV-I) antibody by the enzyme-linked immunosorbent assay (ELISA) and the Western Blot analysis (WB). Attempts to isolate enteroviruses (including poliovirus) from faecal material in both tissue culture and suckling mice were unsuccessful; in addition, acute and convalescent paired serum samples did not show any evidence of recent poliovirus infection when tested against the three serotypes. Specific tests for detection of Epstein-Barr virus infection were not performed; however, the Paul-Bunnel test yielded negative results. ELISA for detection of anti-cytomegalovirus IgM was also negative. The concomitant occurrence of either adult T cell leukemia (ATL) or lymphoma was not recorded in this case.

Impairment Questions and Answers

1999 ◽  
Vol 4 (4) ◽  
pp. 4-4
Keyword(s):  
Symptom Validity ◽  
Validity Testing ◽  
Symptom Validity Testing ◽  
Negative Results ◽  
Tunnel Vision ◽  
Questions And Answers ◽  
Blurry Vision ◽  
Fatigue Evaluation ◽  
Choice Testing ◽  
Rule Out

Abstract Symptom validity testing, also known as forced-choice testing, is a way to assess the validity of sensory and memory deficits, including tactile anesthesias, paresthesias, blindness, color blindness, tunnel vision, blurry vision, and deafness—the common feature of which is a claimed inability to perceive or remember a sensory signal. Symptom validity testing comprises two elements: A specific ability is assessed by presenting a large number of items in a multiple-choice format, and then the examinee's performance is compared with the statistical likelihood of success based on chance alone. Scoring below a norm can be explained in many different ways (eg, fatigue, evaluation anxiety, limited intelligence, and so on), but scoring below the probabilities of chance alone most likely indicates deliberate deception. The positive predictive value of the symptom validity technique likely is quite high because there is no alternative explanation to deliberate distortion when performance is below the probability of chance. The sensitivity of this technique is not likely to be good because, as with a thermometer, positive findings indicate that a problem is present, but negative results do not rule out a problem. Although a compelling conclusion is that the examinee who scores below probabilities is deliberately motivated to perform poorly, malingering must be concluded from the total clinical context.

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