Negative Immunodiffusion Test Results Obtained with Sera of Paracoccidioidomycosis Patients May Be Related to Low-Avidity Immunoglobulin G2 Antibodies Directed against Carbohydrate Epitopes

ABSTRACT Immunodiffusion (ID) is the serologic test most frequently used for the diagnosis and posttherapy follow-up of patients with paracoccidioidomycosis (PCM). The ID test is highly specific (100%), but its sensitivity is relatively low (90%), leading to false-negative results. The aim of this study was to determine the profiles of antibodies in sera from patients with proven PCM and with negative results in the ID test (IDneg) versus positive results in the ID test (IDpos). We analyzed 46 sera from patients with active PCM for total immunoglobulin G (IgG) and IgG subclass responses to Paracoccidioides brasiliensis gp43 antigen (treated or not treated with sodium metaperiodate) by enzyme-linked immunosorbent assay and immunoblotting. Immunoblotting showed that both IDneg and IDpos sera recognized predominantly the gp43 fraction of the P. brasiliensis antigen used in the ID test. IDneg sera contain low-avidity antibodies, low levels of specific IgG (total) and IgG1, and high levels of IgG2 compared with IDpos sera. The antibodies present in IDneg sera were predominantly directed against carbohydrate epitopes, since treatment with sodium metaperiodate resulted in a significant decrease in antibody reactivity. These data suggest that the lack of reactivity of sera from PCM patients in the ID test may be related to the production of low-avidity IgG2 antibodies directed against carbohydrate epitopes.

Download Full-text

False Covid-19 Test Results – Could We Do Things Better? A Personal Opinion

Asian Journal of Pharmacy Nursing and Medical Sciences ◽

10.24203/ajpnms.v8i5.6349 ◽

2020 ◽

Vol 8 (5) ◽

Author(s):

Suzanne Lisbeth Ekelund

Keyword(s):

False Positive ◽

False Negative ◽

Test Results ◽

Negative Results ◽

False Negative Results ◽

Personal Opinion ◽

Potential Problems

This paper describes the problems with false covid-19 test results, both false positive and false negative results. The problems are related to the quality of tests, test sampling and the currently limited follow-up procedures. A test and follow-up strategy that could decrease the potential problems is suggested.

Download Full-text

Scoring System for the Diagnosis of COVID-19

The Open Public Health Journal ◽

10.2174/1874944502013010413 ◽

2020 ◽

Vol 13 (1) ◽

pp. 413-414 ◽

Cited By ~ 1

Author(s):

Mohamed Farouk Allam

Keyword(s):

Scoring System ◽

Clinical Symptoms ◽

False Negative ◽

Nasopharyngeal Swab ◽

Rt Pcr ◽

Pcr Assay ◽

Negative Results ◽

False Negative Results ◽

Symptoms And Signs

Due to the international spread of COVID-19, the difficulty of collecting nasopharyngeal swab specimen from all suspected patients, the costs of RT-PCR and CT, and the false negative results of RT-PCR assay in 41% of COVID-19 patients, a scoring system is needed to classify the suspected patients in order to determine the need for follow-up, home isolation, quarantine or the conduction of further investigations. A scoring system is proposed as a diagnostic tool for suspected patients. It includes Epidemiological Evidence of Exposure, Clinical Symptoms and Signs, and Investigations (if available). This scoring system is simple, could be calculated in a few minutes, and incorporates the main possible data/findings of any patient.

Download Full-text

Comparative study of Allergy Explorer (ALEX) versus ImmunoCAP platforms

Rossiiskii Allergologicheskii ZHurnal ◽

10.36691/raj.2.020.17.1.007 ◽

2020 ◽

Vol 17 (1) ◽

pp. 66-84

Author(s):

C Nerelius ◽

M Andersson ◽

L Sogaard ◽

M Schwanbeck ◽

S Kofler ◽

...

Keyword(s):

Dynamic Range ◽

False Negative ◽

Specific Ige ◽

Test Results ◽

Technical Performance ◽

Negative Results ◽

Allergen Components ◽

False Negative Results ◽

Low Dynamic Range ◽

Immunocap Isac

Objective. In this study, technical performance of the new multiplex ALEX test was compared with results from ImmunoCAP single tests (tIgE, sIgE) and the multiplex platform ImmunoCAP ISAC sIgE 112. Materials and methods. Eleven whole allergen extracts and corresponding allergen components from different allergen groups were used for the analysis of 64-66 patients’ sera by all three platforms. Results. For the whole allergens, 55% false negative results were obtained with the ALEX test comparing to the ImmunoCAP sIgE tests while for allergen components the ALEX test gives 33% false negative results when compared to ImmunoCAP sIgE test results. Additionally, the ALEX test is characterized by a low dynamic range - the platform demonstrated no results above 36 kUA/L for samples giving >100 kUA/L using ImmunoCAP Specific IgE tests in the analysis of sIgE response to the whole allergens. For the allergen components, ALEX showed no results above 38 kUA/L for samples of up to 150 kUA/L according to ImmunoCAP Specific IgE test results. Comparing to ImmunoCAP single plex tests, ALEX show low dynamic range and poor agreement in quantitative results for tIgE and sIgE both for whole allergens and allergen components, while in the comparison with ImmunoCAP ISAC sIgE 112 platform, the agreement is better, but the sensitivity and dynamic range are still low._ Conclusions. The ALEX test has some serious limitations in its performance comparing to both types of ImmunoCAP platforms.

Download Full-text

Comparative study of Allergy Explorer (ALEX) versus ImmunoCAP platforms

Rossiiskii Allergologicheskii ZHurnal ◽

10.36691/raj.2020.17.1.007 ◽

2020 ◽

Vol 17 (1) ◽

pp. 66-84

Author(s):

C Nerelius ◽

M Andersson ◽

L Sogaard ◽

M Schwanbeck ◽

S Kofler ◽

...

Keyword(s):

Dynamic Range ◽

False Negative ◽

Specific Ige ◽

Test Results ◽

Technical Performance ◽

Negative Results ◽

Allergen Components ◽

False Negative Results ◽

Low Dynamic Range ◽

Immunocap Isac

Objective. In this study, technical performance of the new multiplex ALEX test was compared with results from ImmunoCAP single tests (tIgE, sIgE) and the multiplex platform ImmunoCAP ISAC sIgE 112. Materials and methods. Eleven whole allergen extracts and corresponding allergen components from different allergen groups were used for the analysis of 64-66 patients sera by all three platforms. Results. For the whole allergens, 55% false negative results were obtained with the ALEX test comparing to the ImmunoCAP sIgE tests while for allergen components the ALEX test gives 33% false negative results when compared to ImmunoCAP sIgE test results. Additionally, the ALEX test is characterized by a low dynamic range - the platform demonstrated no results above 36 kUA/L for samples giving 100 kUA/L using ImmunoCAP Specific IgE tests in the analysis of sIgE response to the whole allergens. For the allergen components, ALEX showed no results above 38 kUA/L for samples of up to 150 kUA/L according to ImmunoCAP Specific IgE test results. Comparing to ImmunoCAP single plex tests, ALEX show low dynamic range and poor agreement in quantitative results for tIgE and sIgE both for whole allergens and allergen components, while in the comparison with ImmunoCAP ISAC sIgE 112 platform, the agreement is better, but the sensitivity and dynamic range are still low._ Conclusions. The ALEX test has some serious limitations in its performance comparing to both types of ImmunoCAP platforms.

Download Full-text

S235 – Diagnostic Test Validation: CHAMP in Endolymphatic Hydrops

Otolaryngology ◽

10.1016/j.otohns.2008.05.410 ◽

2008 ◽

Vol 139 (2_suppl) ◽

pp. P154-P154

Author(s):

Eveling Y Rojas ◽

Leonardo Ordoñez ◽

Victor Hernandez ◽

Jose E Guzman ◽

Juan Izquierdo ◽

...

Keyword(s):

Diagnostic Test ◽

Endolymphatic Hydrops ◽

False Negative ◽

High Specificity ◽

Diagnostic Value ◽

Clinical Value ◽

Negative Results ◽

False Negative Results ◽

The Relationship

Objectives The Cochlear Hydrops Analysis Masking Procedure (CHAMP) has been reported with a high sensibility and specificity for the diagnosis of endolymphatic hydrops (ELH). Nevertheless, a complete validation of CHAMP with precise methods has not been done. Our objectives: To determine whether CHAMP has a diagnostic value in patients with definite, probable/possible diagnosis of Meniere's disease or endolymphatic hydrops, based on the criteria of the AAO-HNS. Methods Prospective validation study for a diagnostic test: phase II. Latency of wave V was assessed using CHAMP. We classified subjects in 5 groups: 1-Definite ELH, 2-Probable ELH, 3-Possible ELH, 4-subjects with other otovestibular symptoms, 5-normal hearing subjects. We included cases (groups 1–4) with an episode of vertigo with duration equal or longer than 20 minutes, with or without other otovestibular symptoms. Results We included 67 cases (132 ears). 38 cases (76 ears) completed the follow up and their results are presented. In group 1, the sensibility of CHAMP was 43% and its specificity was 100%. In groups 2–3, the sensitivity was 20% and the specificity 100%, with 0% false positive and 80% false negative results. Other indicators of validity for this diagnostic test are presented. Conclusions CHAMP has a high specificity and low sensibility for the diagnosis of ELH when the delay in wave V latency is used. Future studies may assess the relationship between wave amplitudes to improve the clinical value of CHAMP.

Download Full-text

Three highly sensitive "bedside" serum and urine tests for pregnancy compared

Clinical Chemistry ◽

10.1093/clinchem/36.9.1686 ◽

1990 ◽

Vol 36 (9) ◽

pp. 1686-1688 ◽

Cited By ~ 10

Author(s):

H Christensen ◽

H H Thyssen ◽

O Schebye ◽

A Berget

Keyword(s):

Paired Comparison ◽

False Negative ◽

Diagnostic Sensitivity ◽

Enzyme Linked Immunosorbent Assay ◽

Serum Samples ◽

Negative Results ◽

False Negative Results ◽

Significant Difference ◽

Comparison Of The Results ◽

Urine And Serum

Abstract We examined three enzyme-linked immunosorbent assay (ELISA) kits for human choriogonadotropin (hCG) (pregnancy tests) for use with urine and serum samples: the Tandem Icon II hCG Urine and Tandem Icon II hCG Serum, the NovoClone Target hCG Test, and the Abbott TestPacks hCG-urine and hCG-serum. Paired comparison of the results from each kit indicated that the NovoClone Target assay showed significantly lower diagnostic sensitivity (P less than 0.05) than did the Tandem Icon II or Abbott TestPack, both for urine and for serum samples. None of the products demonstrated any significant difference (P greater than 0.05) in diagnostic specificity, but the NovoClone Target kit showed several serious false-negative results with both urine and serum. Paired testing of urine kits vs serum kits also showed no significant differences (P greater than 0.05) in diagnostic sensitivity or specificity. We found the Abbott kits to be the most convenient to use and to read.

Download Full-text

Assessment of the IgA Immunoassay Diagnostic Potential of the Mycobacterium tuberculosis MT10.3-MPT64 Fusion Protein in Tuberculous Pleural Fluid

Clinical and Vaccine Immunology ◽

10.1128/cvi.00372-10 ◽

2010 ◽

Vol 17 (12) ◽

pp. 1963-1969 ◽

Cited By ~ 10

Author(s):

Leonardo Silva Araujo ◽

Renata Maciel Moraes ◽

Anete Trajman ◽

Maria Helena Féres Saad

Keyword(s):

Pleural Fluid ◽

Histopathological Examination ◽

False Negative ◽

High Sensitivity ◽

Enzyme Linked Immunosorbent Assay ◽

Negative Results ◽

Diagnostic Potential ◽

False Negative Results ◽

Sds Page ◽

Increased Sensitivity

ABSTRACT Pleural tuberculosis (PL-TB) remains difficult to diagnose. An enzyme-linked immunosorbent assay (ELISA) was developed based on a construction containing the fusion of the Rv3019c (MT10.3) and Rv1980c (MPT64) gene sequences, and its performance was evaluated in an area where TB is endemic. A total of 92 pleural fluid (PF) samples at serial dilutions of 1:50 to 1:800 were included in the ELISA IgA MT10.3-MPT64 evaluation: 70 from TB patients and 22 from patients with other pleurisies. Confirmation of the expression and subsequent purification of the protein was made by SDS-PAGE and Western blot assays, resulting in a 36-kDa protein. ELISA IgA MT10.3-MPT64 showed sensitivities of 61.4%, 58.6%, 62.9%, 67.1%, and 70% at each PF dilution, respectively. The cumulative results of all dilutions increased sensitivity to 81.4% without jeopardizing specificity. Similar results were also obtained at the combined dilutions of 1:50, 1:200, and 1:800 or 1:50 plus 1:800 dilutions (80%). The overall sensitivity of the reference test, i.e., histopathological examination, was 74%. But, via the ELISA IgA MT10.3-MPT64 test, sensitivity was high for specimens with a negative culture (23/27; 85.2%) or nonspecific histopathology (17/18; 94.4%). Our findings demonstrated the promising use of this test as an adjunct in PL-TB diagnoses, particularly in cases with lower bacterial loads and false-negative results in the reference tests, since the new test includes such important features as quick and easy application, high sensitivity and, perhaps most importantly, affordability, which is so crucial for its widespread use in developing countries.

Download Full-text

Imaging-Cytology Correlation of Thyroid Nodules with Initially Benign Cytology

International Journal of Endocrinology ◽

10.1155/2014/491508 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 7

Author(s):

Shin Hye Hwang ◽

Ji Min Sung ◽

Eun-Kyung Kim ◽

Hee Jung Moon ◽

Jin Young Kwak

Keyword(s):

Thyroid Nodules ◽

False Negative ◽

Needle Aspiration ◽

Malignancy Rate ◽

Negative Results ◽

False Negative Results ◽

Significant Difference ◽

Risk Of Malignancy ◽

Us Findings

Objective. To determine the role of imaging-cytology correlation in reducing false negative results of fine-needle aspiration (FNA) at thyroid nodules.Methods. This retrospective study included 667 nodules 1 cm or larger in 649 patients diagnosed as benign at initial cytologic evaluation and that underwent follow-up ultrasound (US) or FNA following a radiologist’s opinion on concordance between imaging and cytologic results. We compared the risk of malignancy of nodules classified into subgroups according to the initial US features and imaging-cytology correlation.Results. Among included nodules, 11 nodules were proven to be malignant (1.6%) in follow-up FNA or surgery. The malignancy rate was higher in nodules with suspicious US features (11.4%) than in nodules without suspicious US features (0.5%,P<0.001). When a thyroid nodule had discordant US findings on image review after having benign FNA results, malignancy rate increased to 23.3%, significantly higher than that of nodules with suspicious US features (P<0.001). However, no significant difference was found in the risk of malignancy between the nodules without suspicious US features (0.5%) and imaging-cytology concordant nodules (0.6%,P=0.438).Conclusions. Repeat FNA can be effectively limited to patients with cytologically benign thyroid nodules showing discordance in imaging-cytology correlation after initial biopsy, which reduces unnecessary repeat aspirations.

Download Full-text

Spinal arteriovenous shunts: accuracy of shunt detection, localization, and subtype discrimination using spinal magnetic resonance angiography and manual contrast injection using a syringe

Journal of Neurosurgery Spine ◽

10.3171/2015.7.spine15319 ◽

2016 ◽

Vol 24 (4) ◽

pp. 664-670 ◽

Cited By ~ 5

Author(s):

Kittisak Unsrisong ◽

Siriporn Taphey ◽

Kanokporn Oranratanachai

Keyword(s):

False Negative ◽

Injection Technique ◽

Contrast Injection ◽

Accuracy Rate ◽

Negative Results ◽

False Negative Results ◽

Contrast Enhanced ◽

Arteriovenous Shunts ◽

Arterial Feeder

OBJECT The object of this study was to evaluate the accuracy of fast 3D contrast-enhanced spinal MR angiography (MRA) using a manual syringe contrast injection technique for detecting and evaluating spinal arteriovenous shunts (AVSs). METHODS This was a retrospective study of 15 patients and 20 spinal MRA and catheter angiography studies. The accuracy of using spinal MRA to detect spinal AVS, localize shunts, and discriminate the subtype and dominant arterial feeder of the AVS were studied. RESULTS There were 14 pretherapeutic and 6 posttherapeutic follow-up spinal MRA and catheter spinal angiography studies. The spinal AVS was demonstrated in 17 of 20 studies. Spinal MRA demonstrated 100% sensitivity for detecting spinal AVS with no false-negative results. A 97% accuracy rate for AVS subtype discrimination and shunt level localization was achieved using this study's diagnostic criteria. The detection of the dominant arterial feeder was limited to 9 of these 17 cases (53%). CONCLUSIONS The fast 3D contrast-enhanced MRA technique performed using manual syringe contrast injection can detect the presence of a spinal AVS, locate the shunt level, and discriminate AVS subtype in most cases, but is limited when detecting small arterial feeders.

Download Full-text

Repeat FNA Significantly Lowers Number of False Negative Results in Patients with Benign Nodular Thyroid Disease and Features of Chronic Thyroiditis

International Journal of Endocrinology ◽

10.1155/2014/967381 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Dorota Słowińska-Klencka ◽

Ewa Woźniak-Oseła ◽

Bożena Popowicz ◽

Stanisław Sporny ◽

Mariusz Klencki

Keyword(s):

Thyroid Nodules ◽

Benign Lesion ◽

False Negative ◽

Repeat Biopsy ◽

Chronic Thyroiditis ◽

Negative Results ◽

False Negative Results ◽

Risk Of Malignancy ◽

Ct Features

Purpose. The aim of the study was to compare the risk of thyroid malignancy and efficacy of repeat FNA in patients with thyroid nodules diagnosed cytologically as benign lesion (BL) with features of chronic thyroiditis (BL-CT) and BL without CT features (BL-nCT).Methods. The analysis included 917 patients with BL-CT and 7046 with BL-nCT in the first FNA. Repeat biopsy was carried out in 787 patients of BL-CT and 5147 of BL-nCT; 218 patients of BL-CT and 2462 of BL-nCT were operated; in 88 cases of BL-CT and 563 of BL-nCT both ways of follow-up were available.Results. Outcome of repeat cytology implied surgery more frequently in patients with BL-CT than with BL-nCT—3.2% versus 1.9%,P< 0.05. Incidence of cancer (including incidentalomas) was higher in patients with BL-CT operated after one benign cytology than in patients with two benign FNA outcomes: 10.8% versus 1.6%,P< 0.05. In patients with BL-nCT that difference was not significant: 3.2% versus 2.6%.Conclusions. Patients with thyroid nodules diagnosed as BL with CT features have higher risk of malignancy than patients with BL without CT features. Repeat biopsy significantly lowers percentage of FN results in patients with BL-CT in the first FNA.

Download Full-text