A Negative Antinuclear Antibody Does Not Indicate Autoantibody Negativity in Myositis: Role of Anticytoplasmic Antibody as a Screening Test for Antisynthetase Syndrome

2016 ◽  
Vol 44 (2) ◽  
pp. 223-229 ◽  
Author(s):  
Rohit Aggarwal ◽  
Namrata Dhillon ◽  
Noreen Fertig ◽  
Diane Koontz ◽  
Zengbiao Qi ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
Predictive Value ◽  
Antinuclear Antibody ◽  
High Sensitivity ◽  
Epithelial Cell Line ◽  
Antisynthetase Syndrome ◽  
Control Groups ◽  
Serum Samples ◽  
Cytoplasmic Staining ◽  
Sensitivity Specificity

Objective.To evaluate the utility of anticytoplasmic autoantibody (anti-CytAb) in antisynthetase antibody–positive (anti-SynAb+) patients.Methods.Anti-SynAb+ patients were evaluated for antinuclear antibody (ANA) and anti-CytAb [cytoplasmic staining on indirect immunofluorescence (IIF)] positivity. Anti-SynAb+ patients included those possessing anti-Jo1 and other antisynthetase autoantibodies. Control groups included scleroderma, systemic lupus erythematosus, Sjögren syndrome, rheumatoid arthritis, and healthy subjects. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy of anti-CytAb, and ANA were assessed. Anti-CytAb and ANA testing was done by IIF on human epithelial cell line 2, both reported on each serum sample without knowledge of the clinical diagnosis or final anti-SynAb results.Results.Anti-SynAb+ patients (n = 202; Jo1, n = 122; non-Jo1, n = 80) between 1985–2013 with available serum samples were assessed. Anti-CytAb showed high sensitivity (72%), specificity (89%), NPV (95%), and accuracy (86%), but only modest PPV (54%) for anti-SynAb positivity. In contrast, ANA showed only modest sensitivity (50%) and poor specificity (6%), PPV (9%), NPV (41%), and accuracy (12%). Positive anti-CytAb was significantly greater in the anti-SynAb+ patients than ANA positivity (72% vs 50%, p < 0.001), and 81/99 (82%) ANA-negative patients in the anti-SynAb+ cohort had positive anti-CytAb. In contrast, the control groups showed high rates for ANA positivity (93.5%), but very low rates for anti-CytAb positivity (11.5%). Combining anti-CytAb or Jo1 positivity showed high sensitivity (92%) and specificity (89%) for identification of anti-SynAb+ patients.Conclusion.Assessing patients for anti-CytAb serves as an excellent screen for anti-SynAb+ patients using simple IIF. Cytoplasmic staining should be assessed and reported for patients suspected of having antisynthetase syndrome and a negative ANA should not be used to exclude this diagnosis.

scholarly journals Use of β-D-glucan in diagnosis of suspected Pneumocystis jirovecii pneumonia in adults with HIV infection

2021 ◽  
pp. 095646242110222
Author(s):  
Thomas Juniper ◽  
Chris P Eades ◽  
Eliza Gil ◽  
Harriet Fodder ◽  
Killian Quinn ◽  
...  
Keyword(s):  
Predictive Value ◽  
Diagnostic Tests ◽  
Elevated Serum ◽  
Clinical Information ◽  
High Sensitivity ◽  
Pneumocystis Pneumonia ◽  
Pneumocystis Jirovecii Pneumonia ◽  
Alternative Diagnosis ◽  
Positive Threshold ◽  
Sensitivity Specificity

Objectives: An elevated serum (1-3)-β-D-glucan (BDG) concentration has high sensitivity for a diagnosis of Pneumocystis pneumonia (PCP) in people with HIV (PWH). At the current manufacturer-recommended positive threshold of 80 pg/mL (Fungitell), specificity for PCP is variable and other diagnostic tests are required. We evaluated the utility of serum BDG for diagnosis of suspected PCP in PWH at three inner-London hospitals to determine BDG concentrations for diagnosis and exclusion of PCP. Methods: From clinical case records, we abstracted demographic and clinical information and categorised patients as having confirmed or probable PCP, or an alternative diagnosis. We calculated sensitivity, specificity and positive predictive value (PPV) of serum BDG concentrations >400 pg/mL and negative predictive value (NPV) of BDG <80 pg/mL. Results: 76 patients were included; 29 had laboratory-confirmed PCP, 17 had probable PCP and 30 had an alternative diagnosis. Serum BDG >400 pg/mL had a sensitivity of 83%, specificity of 97% and PPV 97% for diagnosis of PCP; BDG <80 pg/mL had 100% NPV for exclusion of PCP. Conclusions: In PWH with suspected PCP, BDG <80 pg/mL excludes a diagnosis of PCP, whereas BDG concentrations >400 pg/mL effectively confirm the diagnosis. Values 80–400 pg/mL should prompt additional diagnostic tests.

scholarly journals Comparison of Coombs Gel Test with ELISA and Standard Tube Agglutination Tests Used in Serological Diagnosis of Brucellosis

2020 ◽  
Vol 2 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Cigdem Akalan Kuyumcu ◽  
Serpil Erol ◽  
Rıza Adaleti ◽  
Seniha Senbayrak ◽  
Secil Deniz ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Diagnostic Tests ◽  
Serological Test ◽  
High Sensitivity ◽  
Serological Diagnosis ◽  
Control Groups ◽  
Serum Samples ◽  
Serological Tests ◽  
Reliable Test ◽  
And Control

Objective: Serological tests are the most commonly used tests in the diagnosis of brucellosis; however, each serological test has some drawbacks. In this study, we aimed to determine the value of the Brucella Coombs gel test (BCGT) in the serological diagnosis of brucellosis in comparison with Standard tube agglutination (STA) and ELISA tests. Materials and Methods: The study included 42 patients who were considered to have brucellosis as a preliminary diagnosis. BCGT, Brucella-IgM/IgG ELISA, and STA tests were performed from serum samples of the patients. The correlation of the diagnostic tests was analyzed using Cohen’s Kappa Analysis.  Results: Twenty-seven (64.2%) of 42 patients were diagnosed with brucellosis according to their medical history and clinical and serological tests. The sensitivity and specificity of BCGT to diagnose brucellosis was 96.2%, and 100%, respectively. The sensitivity and specificity for the diagnosis of brucellosis 62.9% and 100% for STA, respectively; 33.3% and 66.6% for Brucella-IgM; and 66.6% and 100% for Brucella-IgG. BCGT was significantly correlated with STA (κ= 0.590) and Brucella-IgG (κ=0.539) Conclusion: BCGT can be utilized as a simple and reliable test in the diagnosis of brucellosis with high sensitivity and specificity. Nevertheless, the sensitivity and specificity of BCGT should be demonstrated by comprehensive studies, including culture-confirmed cases and control groups.

scholarly journals XPERT MYCOBACTERIUM TUBERCULOSIS/RIFAMPICIN ASSAY: A BOON IN TUBERCULOSIS DIAGNOSTICS

2016 ◽  
Vol 9 (5) ◽  
pp. 225 ◽  
Author(s):  
Sevitha Bhat ◽  
Kavya Ramamurthy ◽  
Shalini Shenoy ◽  
Aseem Rangnekar
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Predictive Value ◽  
High Sensitivity ◽  
Mortality And Morbidity ◽  
Indicator Tube ◽  
Promising Tool ◽  
Causes Of Mortality ◽  
Conventional Microscopy ◽  
Tb Diagnostics ◽  
Sensitivity Specificity

ABSTRACTObjectives: Mycobacterium tuberculosis (MTB) remains one of the most significant causes of mortality and morbidity in developing countriesespecially India. India has the highest burden of TB, with an estimated incidence figure of 2.1 million cases out of the 9 million cases of TB globally.Diagnosis of TB relies on conventional microscopy and culture with drawbacks related to sensitivity, specificity, turn around time (TAT). The aim ofthis study was to evaluate the performance of Xpert MTB/rifampicin (RIF) assay (GX) for MTB detection in pulmonary and extrapulmonary clinicalsamples.Methods: A total of 209 clinical specimens (182: pulmonary and 27: extrapulmonary) were processed using auramine smear, culture by mycobacteriagrowth indicator tube and GenXpert.Results: The sensitivity of GenXpert was 62.63% for pulmonary and 55% for extrapulmonary samples. The sensitivity and specificity of GX were100% for the smear positive cases. The sensitivity, specificity, positive predictive value, and negative predictive value of the GX for smear negativecases were 67.8%, 97.5%, 90.4%, and 89.6%, respectively. RIF resistance was detected in 3.8% the samples.Conclusion: GenXpert, with short TAT, high sensitivity, specificity and less technical expertise required is a promising tool in TB diagnostics for thefuture.Keywords: GenXpert, Tuberculosis diagnosis, Molecular method, Rifampicin resistance.

scholarly journals Role of MRI in the Diagnosis of Injury to the Lisfranc Ligament Complex

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0029
Author(s):  
Christopher Kreulen ◽  
Eric Giza ◽  
Eva Escobedo ◽  
Cyrus Bateni ◽  
Michael Doherty
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
High Sensitivity ◽  
Lisfranc Injury ◽  
Radiology Reports ◽  
Lisfranc Ligament ◽  
Sensitivity Specificity

Category: Sports Introduction/Purpose: Subtle Lisfranc ligamentous injuries are difficult to diagnose and magnetic resonance is becoming a useful tool. The purpose of this study is to evaluate the efficacy of magnetic resonance (MR) imaging for the diagnosis of injuries of the Lisfranc ligament complex. Methods: The radiology database was searched between Jan 1, 2010 and Mar 10, 2015 to identify patients over the age of 18 years who had MR imaging of the foot for suspected injury of the Lisfranc ligament complex. MR images were reviewed by 2 fellowship trained musculoskeletal radiologists, whom were blinded to the original radiology reports. Findings were categorized as: no injury or injury present. Injury was deemed to be present if 2 of the 3 components of C1-M2 ligament showed disruption or signal alterations on T1 and T2 weighted images. Disagreements were resolved by consensus. Correlation was made with surgical findings whenever performed. In patients not undergoing surgery, the presence or absence of injury was determined by clinical examination performed by an orthopedic surgeon and follow-up. Sensitivity, specificity, positive predictive value(PPV), and negative predictive value (NPV) of MR for diagnosis of Lisfranc ligament complex injury was determined. Results: Of 60 patients, 9 were excluded due to a lack of follow-up. Lisfranc injury was determined to be present on MR in 26 patients and 18 underwent surgery. Injury was confirmed in 16, and 2 were intact. 2 patients underwent closed reduction and were clinically determined to be injured. 6 of the injured 26 patients were sprained and not injured/torn on clinical evaluation. Of the 25 patients determined to have no injury on MR, 24 were intact clinically. 1 patient had a Lisfranc injury on follow-up. Sensitivity, specificity, PPV and NPV of MR for detection of significant Lisfranc injury were 94.7% (CI: 73.9% to 99.9%), 75% (CI: 56.6% to 88.5%), 69.2% (CI: 55% to 80.5%) and 96% (CI: 77.9% to 99.4%) respectively. Conclusion: MR has a high sensitivity and negative predictive value for diagnosis of injury to the Lisfranc ligament complex. MR of the foot should be considered in patients with clinical suspicion of injury to the Lisfranc ligament complex, and it is highly accurate in excluding such injuries.

Therapeutic drug monitoring of adalimumab in RA: no predictive value of adalimumab serum levels and anti-adalimumab antibodies for prediction of response to the next bDMARD

2020 ◽  
Vol 79 (7) ◽  
pp. 867-873
Author(s):  
Evy Ulijn ◽  
Nathan den Broeder ◽  
Maike Wientjes ◽  
Noortje van Herwaarden ◽  
Inger Meek ◽  
...  
Keyword(s):  
Predictive Value ◽  
Evidence Synthesis ◽  
Serum Levels ◽  
Subsequent Treatment ◽  
Therapeutic Drug ◽  
Test Accuracy ◽  
Serum Samples ◽  
Best Evidence Synthesis ◽  
Adalimumab Treatment ◽  
Sensitivity Specificity

BackgroundAfter adalimumab treatment failure, tumour necrosis factor inhibition (TNFi) and non-TNFi biological disease-modifying anti-rheumatic drugs (bDMARDs) are equally viable options on a group level as subsequent treatment in rheumatoid arthritis (RA) based on the current best evidence synthesis. However, preliminary data suggest that anti-adalimumab antibodies (anti-drug antibodies, ADA) and adalimumab serum levels (ADL) during treatment predict response to a TNFi as subsequent treatment.ObjectiveTo validate the association of presence of ADA and/or low ADL with response to a subsequent TNFi bDMARD or non-TNFi bDMARD. Sub-analyses were performed for primary and secondary non-responders.MethodsA diagnostic test accuracy retrospective cohort study was done in consenting RA patients who discontinued adalimumab after >3 months of treatment due to inefficacy and started another bDMARD. Inclusion criteria included the availability of (random timed) serum samples between ≥8 weeks after start and ≤2 weeks after discontinuation of adalimumab, and clinical outcome measurements Disease Activity Score in 28 joints - C-reactive protein (DAS28-CRP) between 3 to 6 months after treatment switch. Test characteristics for EULAR (European League Against Rheumatism) good response (DAS28-CRP based) after treatment with the next (non-)TNFi bDMARD were assessed using area under the receiver operating characteristic and sensitivity/specificity.Results137 patients were included. ADA presence was not predictive for response in switchers to a TNFi (sensitivity/specificity 18%/75%) or a non-TNFi (sensitivity/specificity 33%/70%). The same was true for ADL levels in patients that switched to a TNFi (sensitivity/specificity 50%/52%) and patients that switched to a non-TNFi (sensitivity/specificity 32%/69%). Predictive value of ADA and ADL were similar for both primary and secondary non-responders to adalimumab.ConclusionsIn contrast to earlier research, we could not find predictive value for response to a second TNFi or non-TNFi for either ADA or random timed ADL.

Isolated demyelinating syndromes: comparison of CSF oligoclonal bands and different MR imaging criteria to predict conversion to CDMS

2001 ◽  
Vol 7 (6) ◽  
pp. 359-363 ◽  
Author(s):  
M Tintoré ◽  
A Rovira ◽  
L Brieva ◽  
E Grivé ◽  
R Jardí ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Positive Predictive Value ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
High Sensitivity ◽  
Oligoclonal Bands ◽  
High Negative Predictive Value ◽  
Csf Oligoclonal Bands ◽  
Sensitivity Specificity

Aim of the study: To evaluate and compare the capacity of oligoclonal bands (OB) and three sets of MR imaging criteria to predict the conversion of clinically isolated syndromes (CIS) to clinically definite multiple sclerosis (CDMS). Patients and methods: One hundred and twelve patients with CIS were prospectively studied with MR imaging and determination of OB. Based on the clinical follow-up (conversion or not conversion to CDMS), we calculated the sensitivity, specificity accuracy, positive and negative predictive value of the OB, and MR imaging criteria proposed by Paty et al, Fazekas et al and Barkhof et al. Results: CDMS developed in 26 (23.2%) patients after a mean follow-up of 31 months (range 12-62). OB were positive in 70 (62.5%) patients and were associated with a higher risk of developing CDMS. OB showed a sensitivity of 81%, specificity of 43%, accuracy of 52%, positive predictive value (PPV) of 30% and negative predictive value (NPV) of 88%. Paty and Fazekas criteria showed the same results with a sensitivity of 77%, specificity of 51%, accuracy of 57%, positive predictive value of 32% and negative predictive value of 88%. Barkhof criteria showed a sensitivity of 65%, specificity of 70%, accuracy of 69%, PPV of 40% and NPV of 87%. The greatest accuracy was achieved when patients with positive OB and three or four Barkhof's criteria were selected. Conclusions: We observed a high prevalence of OB in CIS. OB and MR imaging (Paty's and Fazekas' criteria) have high sensitivity. Barkhof's criteria have a higher specificity. Both OB and MR imaging criteria have a high negative predictive value.

scholarly journals Association of Immunofluorescence pattern of Antinuclear Antibody with Specific Autoantibodies in the Bangladeshi Population

2015 ◽  
Vol 40 (2) ◽  
pp. 74-78 ◽  
Author(s):  
S Sharmin ◽  
S Ahmed ◽  
A Abu Saleh ◽  
F Rahman ◽  
MR Choudhury ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Lupus Erythematosus ◽  
Antinuclear Antibody ◽  
Research Work ◽  
Connective Tissue Disorder ◽  
Nuclear Antigen ◽  
Dot Blot ◽  
Serum Samples ◽  
Speckled Pattern ◽  
Extractable Nuclear Antigen

Antinuclear antibody (ANA) is useful in the diagnosis of connective tissue disorder (CTD). Association of specific autoantibodies with the immunofluorescence pattern of ANA in CTD, noted in western literature has been considered as reference in all over the world. However, in Bangladesh no such research work or data correlating the autoantibodies and their ANA patterns is found. Objective of the study was to identify an association between immunofluorescence patterns of antinuclear antibody on HEp-2 cell and more specific antinuclear reactivities (e.g. anti-dsDNA and anti-extractable nuclear antigen) in the serum samples of CTD patients. Serum samples of 152 CTD patients (Systemic lupus erythematosus, Rhumatoid arthritis, Sjogren´s syndrome, Systemic sclerosis, Polymyositis, Mixed connective tissue disease) were diagnosed clinically, attending at Bangabandhu Sheikh Mujib Medical University (BSMMU) during the study period of January, 2010 to December, 2010. Samples were subjected for ANA testing by Indirect Immunofluorescence (IIF) on HEp-2 cell (ALPHADIA) in dilution of 1:40, anti-dsDNA by ELISA and anti- extractable nuclear antigen (anti-ENA) by Dot Immunoblot. Dot blot strips were tested for anti-Sm, anti-RNP, anti-SSA/Ro, anti-SSB/La, anti-Scl-70 and anti-Jo-1. Out of 152 patients 110 (72.3%) cases were ANA positive by IIF on HEp-2 cell. ANA positive sera exhibited four fluorescence patterns such as speckled (50.8%), peripheral (21.6%) ,homogenous (18.1%) and nucleolar pattern (9%). Peripheral pattern and homogenous pattern was predominantly associated with anti-dsDNA (p<0.05). Speckled pattern was significantly associated with anti-ENA (p<0.05).The most commonly identified antinuclear autoreactivity was directed towards anti-RNP (25.7%) then anti-Scl-70 (20%), anti-SSA (14.2%) and anti-SSB (5.7%). Multiple anti-ENA reactivities were identified in 34.28% cases. Peripheral and homogenous pattern is strongly associated with anti-dsDNA and speckled pattern may predict anti-ENA (specially ribonucleoprotiens). As a definite correlation between the ANA patterns and the group of antibodies was detected by dot immunoblot, one could predict presence of certain specific auto antibodies for a particular ANA pattern identified. This may restrict on the cost of laboratory investigations in a developing country like Bangladesh. Thus, ANA-IIF method may reduce the expense of detailed immunological work-up with minimal loss in diagnostic accuracy.Bangladesh Med Res Counc Bull 2014; 40 (2): 74-78

Sensitivity, Specificity, and Positive Predictive Value of Technetium 99-HMPAO SPECT in Discriminating Alzheimer's Disease from other Dementias

1997 ◽  
Vol 10 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Donna L. Masterman ◽  
Mario F. Mendez ◽  
Lynn A. Fairbanks ◽  
Jeffrey L. Cummings
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Positive Predictive Value ◽  
Predictive Value ◽  
Single Photon ◽  
Photon Emission ◽  
High Sensitivity ◽  
Hmpao Spect ◽  
Clinical Diagnoses ◽  
Sensitivity Specificity

Investigators have reported high sensitivity and specificity values for single photon emission computerized tomography (SPECT) when distinguishing Alzheimer's disease (AD) patients from normal elderly controls or from selected patient groups. The role of SPECT in identifying AD among unselected patients with memory complaints requires investigation. We examined 139 consecutive patients with 99Tc-HMPAO SPECT. NINCDS-ADRDA diagnoses were determined blind to SPECT results, and scans were read and classified by visual inspection blind to clinical diagnoses. Bilateral temporoparietal hypoperfusion (TP) occurred in 75% of probable, 65% of possible, and 45% of unlikely AD patients, yielding a sensitivity of 75% and a specificity of 52% when comparing probable AD versus unlikely AD groups. A positive predictive value of 78% was obtained based on a 69% prevalence of AD in our total clinic population. Patients with false-positive results included a variety of dementing illnesses; all patients with bilateral hypoperfusion had dementia. A pattern of TP on SPECT scans is seen in most patients with AD, but could be found in other dementias as well and cannot be regarded as specific to AD. Reduced TP perfusion discriminated between demented and nondemented individuals. Further strategies for SPECT interpretation that improve diagnostic specificity should be sought.

The predictive value of videostroboscopy in the assessment of premalignant lesions and early glottis cancers

2017 ◽  
Vol 71 (4) ◽  
pp. 14-18 ◽  
Author(s):  
Anna Rzepakowska ◽  
Ewelina Sielska-Badurek ◽  
Ewa Osuch-Wójcikiewicz ◽  
Michał Sobol ◽  
Kazimierz Niemczyk
Keyword(s):  
Predictive Value ◽  
Vocal Fold ◽  
Histopathological Examination ◽  
High Sensitivity ◽  
Vocal Folds ◽  
Invasive Cancer ◽  
Premalignant Lesions ◽  
Good Tool ◽  
Malignant Lesions ◽  
Sensitivity Specificity

Objective: To assess the sensitivity and specificity of larngovideostroboscopy (LVS) in the diagnosis of precancerous and malignant lesions of the vocal folds. Material and methods: In 175 patients (128 men and 47 women), aged 19-88 years, mean age 61.5, who were admitted to the clinic with diagnosed premalignant conditions of vocal fold mucosa (leukoplakia, chronic hypertrophic inflammatory lesions) and thickening or tumor on the vocal fold, there was performed LVS before the laryngeal microsurgery. The LVS study included: localization of the leasion, movement of the vocal folds, mucosal wave, shape of glottis clousure, amplitude and symmetry of vocal fold vibration. In the evaluation, a point scale was applied for the individual functional parameters. The scale ranged from 0 to 14. Patients with impaired vocal fold motion or absent mucosal wave were positive on LVS for malignant lesions. Those with limitted mucosal wave were positive on LVS for dysplastic lesions. The results were compared with the final histopathological examination and the sensitivity, specificity, accuracy, positive (PPV) and negative (NPV) predictive value were calculated. Results: On the basis of histopathological examination, benign lesions (normal or inflammatory mucosa) accounted for 20% of diagnoses, hypertrophy and parakeratosis for 28%, low and middle grade dysplasia accounted for 10% and malignant lesions (high-grade dysplasia, pre-invasive cancer, Invasive cancer) was diagnosed in 42% of patients. The overall mean score for LVS was 4.5 and 8.0, respectively for benign and malignant lesions. Sensitivity, specificity, accuracy, PPV and NPV of LVS in detecting malignant lesions were respectively - 95.6%, 23.8%, 61.1%, 57.6% and 83.3% and in detecting both premalignant and malignant lesions were respectively – 90.7%, 31.4%, 78.9%, 84.1% and 45.8%. Conclusions: Because of the high sensitivity of LVS in detecting precancerous and malignant lesions, this method is a very good tool for screening of pathology within the larynx.

A unique antiphospholipid assay recognizing phospholipid mixture compared with criteria antiphospholipid immunoassays in lupus patients

Lupus ◽  
2016 ◽  
Vol 26 (6) ◽  
pp. 606-615 ◽  
Author(s):  
Y Zuo ◽  
R Willis ◽  
E Papalardo ◽  
M Petri ◽  
E N Harris ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
Clinical Manifestations ◽  
Case Series ◽  
Likelihood Ratios ◽  
Serum Samples ◽  
Predictive Values ◽  
Pregnancy Morbidity ◽  
Commercial Kits ◽  
Sensitivity Specificity

Background While essential for the classification of antiphospholipid syndrome (APS), anticardiolipin (aCL) assays lack specificity and anti-β2glycoproteinI (anti-β2GPI) assays lack sensitivity in this regard. Our aim was to perform a comparative analysis of the APhL ELISA assay (IgG/IgM) and criteria antiphospholipid (aPL) immunoassays in identifying APS-related clinical manifestations in a large group of patients with systemic lupus erythematosus (SLE). Methods Serum samples from 1178 patients from the Hopkins ( n = 543), LUMINA ( n = 588) and Jamaican SLE cohorts ( n = 47) were examined for IgG/IgM positivity in aCL (in-house), anti-β2GPI (two commercial kits) and APhL (Louisville APL) ELISA assays. Correlation of assay positivity with clinical manifestations and sensitivity, specificity, positive and negative predictive values and likelihood ratios were evaluated. A case series analysis was also performed in patients for whom there was isolated positivity in the specific aPL assays. Results The prevalence of aCL positivity was 34.9%, anti-β2GPI kit A was 22.6%, APhL was 11.5% and anti-β2GPI kit B was 7.6% in the study population. Anti-β2GPI kit B, aCL and APhL assays were correlated with venous thrombosis, while only APhL was significantly correlated with arterial thrombosis and consistently correlated with pregnancy-related morbidity. No significant correlations were noted for anti-β2GPI kit A. Sensitivity was greatest for aCL assays followed by anti-β2GPI kit A, APhL and anti-β2GPI kit B, while specificity was greatest and equal for anti-β2GPI kit B and APhL assays. Conclusions Overall, APhL antibodies, especially IgG, represent a promising biomarker for the classification of APS patients in the context of autoimmunity and in risk assessment with regards to pregnancy morbidity and thrombotic manifestations.

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