scholarly journals Fast Detection And Quantification of Plasmodium Species Infected Erythrocytes In A Non-Endemic Region By Using The Sysmex XN-31 Analyzer

2021 ◽  
Author(s):  
T.A. Khartabil ◽  
Y.B. de Rijke ◽  
R. Koelewijn ◽  
J.J. van Hellemond ◽  
H. Russcher
Keyword(s):  
Diagnostic Accuracy ◽  
Red Blood Cells ◽  
False Positive ◽  
Blood Cells ◽  
False Negative ◽  
Screening Method ◽  
Plasmodium Species ◽  
Endemic Region ◽  
Positive Results ◽  
Detection And Quantification

Abstract BACKGOUND: Due to increased travel from endemic countries, malaria occurs more frequently in non-endemic regions. It is a challenge for diagnostic laboratories in non-endemic countries to provide reliable results, as experience of staff is often limited to only a few cases per year. In this study, we evaluated the diagnostic accuracy of the fully automated Sysmex XN-31 malaria analyzer in a routine diagnostic setting in a non-endemic region. METHODS: Samples from 112 patients suspected for malaria were examined by the Sysmex XN-31 analyzer to determine the absolute count of malaria-infected red blood cells count (MI-RBC/µl). Microscopic examination of both Quantitative Blood Coat capillary tubes and thick and thin blood films were used as reference methods. Limits of blank (LoB), detection (LoD) and quantification (LoQ) were investigated using an in vitro Plasmodium falciparum culture . Nine hundred twenty samples of patients with RBC abnormalities were included to determine which RBC abnormalities trigger indeterminate or false positive results. RESULTS: No false positive nor false negative results were obtained for the examined patient samples suspected for malaria. For 3% of samples an indeterminate result by the XN-31 was obtained. The Passing-Bablok regression line for diagnostic accuracy of the parasitemia was y = 39.75 + 0.7892x showing a positive bias of about 21% when comparing the MI-RBC results to microscopy. The LoB, LoD and LoQ were calculated to be 4.7, 5.9, and 19.0 infected RBC/mL, respectively. From the 920 abnormal RBC samples collected, 4.6% resulted in a false positive MI-RBC result and almost half of the samples produced indeterminate results. These results were related to increases in nucleated red blood cells, reticulocytes and other abnormal RBC morphologies such as sickle cells. CONCLUSIONS: Based on the results we conclude that the XN-31 is a fast and reliable screening method in the detection and quantification of Plasmodium species in patients However, if an abnormal red blood cell morphology is present, the results of the XN-31 should be interpreted with caution as false positive results can be caused by interfering abnormal erythrocytes.

scholarly journals High Diagnostic Accuracy of Antigen Microarray for Sensitive Detection of Hepatitis C Virus Infection

2008 ◽  
Vol 54 (2) ◽  
pp. 424-428 ◽  
Author(s):  
Jung-ah Kwon ◽  
Hyeseon Lee ◽  
Kap N o Lee ◽  
Kwangchun Chae ◽  
Seram Lee ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Detection Limit ◽  
Diagnostic Accuracy ◽  
False Positive ◽  
Sol Gel ◽  
False Negative ◽  
Screening Method ◽  
Confirmatory Test ◽  
Specificity And Sensitivity

Abstract Background: Hepatitis C virus (HCV) can be transmitted through blood transfusion. Screening ELISA, the most widely used method for HCV diagnosis, sometimes yields false-positive and false-negative results, so a confirmatory test is used. This secondary testing is labor-intensive and expensive, and thus is impractical for massive blood bank screening. Therefore, a new massive screening method with high accuracy is needed for sensitive and specific detection of HCV. Methods: With sol-gel material, we designed novel antigen microarray in 96-well plates for HCV detection. Each individual well was spotted with 4 different HCV antigens. We used this new system to test 154 patient serum samples previously tested for HCV by ELISA (87 HCV positive and 67 HCV negative) (HCV EIA3.0, ABBOTT). We assessed the detection limit of our microarray system with the use of serial 10-fold dilutions of an HCV-positive sample. Results: Our microarray assay was reproducible and displayed higher diagnostic accuracy (specificity) (98.78%) than did the ELISA (81.71%). Our method yielded significantly fewer false-positive results than did the ELISA. The detection limit of our assay was 1000 times more sensitive than that of the ELISA. In addition, we found this novel assay technology to be compatible with the currently employed automated methods used for ELISA. Conclusion: We successfully applied the sol-gel–based protein microarray technology to a screening assay for HCV diagnosis with confirmatory test-level accuracy. This new, inexpensive method will improve the specificity and sensitivity of massive sample diagnosis.

Diagnostic accuracy of seven radiographic views, alone and in combination, for diagnosis of pectoral girdle fractures in wild passerines after window collisions

2022 ◽  
pp. 1-6
Author(s):  
Crystal L. Matt ◽  
Nicola Di Girolamo ◽  
Ruth M. Hallman ◽  
Keith L. Bailey ◽  
Timothy J. O’Connell ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
False Positive ◽  
Clinical Relevance ◽  
False Negative ◽  
Pectoral Girdle ◽  
Blinded Observer ◽  
Positive Results ◽  
Limited Accuracy

Abstract OBJECTIVE To determine the prevalence of pectoral girdle fractures in wild passerines found dead following presumed window collision and evaluate the diagnostic accuracy of various radiographic views for diagnosis of pectoral girdle fractures. SAMPLE Cadavers of 103 wild passerines that presumptively died as a result of window collisions. PROCEDURES Seven radiographic projections (ventrodorsal, dorsoventral, lateral, and 4 oblique views) were obtained for each cadaver. A necropsy was then performed, and each bone of the pectoral girdle (coracoid, clavicle, and scapula) was evaluated for fractures. Radiographs were evaluated in a randomized order by a blinded observer, and results were compared with results of necropsy. RESULTS Fifty-six of the 103 (54%) cadavers had ≥ 1 pectoral girdle fracture. Overall accuracy of using individual radiographic projections to diagnose pectoral girdle fractures ranged from 63.1% to 72.8%, sensitivity ranged from 21.3% to 51.1%, and specificity ranged from 85.7% to 100.0%. The sensitivity of using various combinations of radiographic projections to diagnose pectoral girdle fractures ranged from 51.1% to 66.0%; specificity ranged from 76.8% to 96.4%. CLINICAL RELEVANCE Radiography alone appeared to have limited accuracy for diagnosing fractures of the bones of the pectoral girdle in wild passerines after collision with a window. Both individual radiographic projections and combinations of projections resulted in numerous false negative but few false positive results.

Diagnostic pitfall of carryover: in automatic urine analyzers

2016 ◽  
Vol 41 (6) ◽  
Author(s):  
Eren Vurgun ◽  
Osman Evliyaoğlu ◽  
Sembol Yıldırmak ◽  
İbrahim Akarsubaşı
Keyword(s):  
Red Blood Cells ◽  
Microscopic Examination ◽  
False Positive ◽  
Blood Cells ◽  
Gross Hematuria ◽  
Urine Sediment ◽  
Carryover Effect ◽  
Diagnostic Pitfall ◽  
Positive Results ◽  
Very High

AbstractObjective:We aimed to find out whether there is significant carryover effect which causes false-positive hematuria on red blood cells (RBCs) in automatic urine chemistry (DIRUI H-800) and sediment (DIRUI FUS-200) analyzers.Methods:Twenty-four samples with gross hematuria selected as containing high RBC concentration and forty-eight samples which had both negative result in dipstick and 0/hpf in microscopic examination selected as containing low RBC concentration. Carryover% was calculated via the formula [carryover%=100×(bResults:Carryover% was very high (67%) in urine chemistry analyzer. Carryover% of urine sediment analyzer was found 0.4% whilst false-positive hematuria percentage was 87.5% for the first samples came after gross hematuria and 6.6% for the second samples. The first samples analyzed after gross hematuria had significantly higher (p<0.001) results than the second samples in both analyzers.Conclusion:In urine sediment analyzer, carryover% calculated by formula was found analytically sufficient, but it causes highly false-positive results due to diagnostic limit of hematuria (RBC>3/hpf) is low. To prevent carryover in both urine analyzers; washing procedures should be revised and the diagnostic effect of carryover should also be taken into account by biochemists.

Critical Evaluation of Impedance Phlebography for the Diagnosis of Deep Vein Thrombosis

1974 ◽  
Vol 31 (02) ◽  
pp. 273-278
Author(s):  
Kenneth K Wu ◽  
John C Hoak ◽  
Robert W Barnes ◽  
Stuart L Frankel
Keyword(s):  
Deep Vein Thrombosis ◽  
False Positive ◽  
False Negative ◽  
Critical Evaluation ◽  
Original Method ◽  
Vein Thrombosis ◽  
Negative Results ◽  
False Negative Results ◽  
Deep Vein ◽  
Positive Results

SummaryIn order to evaluate its daily variability and reliability, impedance phlebography was performed daily or on alternate days on 61 patients with deep vein thrombosis, of whom 47 also had 125I-fibrinogen uptake tests and 22 had radiographic venography. The results showed that impedance phlebography was highly variable and poorly reliable. False positive results were noted in 8 limbs (18%) and false negative results in 3 limbs (7%). Despite its being simple, rapid and noninvasive, its clinical usefulness is doubtful when performed according to the original method.

Identification of Streptococcus pyogenes in a Pediatric Outpatient Department: A Practical System Designed for Rapid Results and Resident Teaching

PEDIATRICS ◽  
1974 ◽  
Vol 54 (6) ◽  
pp. 718-723
Author(s):  
Katherine Sprunt ◽  
Dorothea Vail ◽  
Russell S. Asnes
Keyword(s):  
False Positive ◽  
Fluorescent Antibody ◽  
False Negative ◽  
Screening Method ◽  
Rapid Screening ◽  
Resident Teaching ◽  
Antibody Uptake ◽  
Busy Clinic ◽  
Group A ◽  
Laboratory Tool

A rapid screening method for identification of clinic patients with pharyngitis who are carrying group A beta-hemolytic streptococci and for teaching residents the values and limitations of the culture-disk approach to identification has been reviewed as developed for a busy clinic and a busy hospital laboratory. Identification of positive cultures in less than 24 hours, using Taxos A disk and specific fluorescent antibody uptake, resulted in 12% apparent false-positive and 3.6% false-negative reports. However, when viewed in the light of the techniques used for verifying results, there were probably 3% false-positive and 3% false-negative reports. The screening method is considered acceptably reliable and practical as a laboratory tool and a resident teaching device.

Three Years of Experience With Random Urinary Homovanillic and Vanillylmandelic Acid Levels in the Diagnosis of Neuroblastoma

PEDIATRICS ◽  
1987 ◽  
Vol 79 (2) ◽  
pp. 203-205
Author(s):  
Mendel Tuchman ◽  
Margaret L. R. Ramnaraine ◽  
William G. Woods ◽  
William Krivit
Keyword(s):  
False Positive ◽  
Homovanillic Acid ◽  
False Negative ◽  
False Negative Rate ◽  
Urine Samples ◽  
Vanillylmandelic Acid ◽  
Test Results ◽  
Upper Limit ◽  
Positive Results ◽  
Rule Out

During the last 3 years, random urine samples from 408 patients were tested for elevated homovanillic acid (HVA) and vanillylmandelic acid (VMA) levels to rule out the diagnosis of neuroblastoma. Thirty-seven of these patients had elevated HVA and/or VMA levels, and neuroblastoma was subsequently diagnosed. In three additional patients with negative test results (normal HVA and VMA levels), tumors were subsequently diagnosed (false-negative rate of 7.5%). Ten percent of the patients with neuroblastoma had normal HVA and 27.5% had normal VMA levels at the time of diagnosis. Only one patient (2.5%) with neuroblastoma had elevated VMA levels in the presence of normal HVA levels. More than 60% of the patients with neuroblastoma had urinary HVA and/or VMA levels higher than twice the upper limit of normal. No false-positive results were encountered. Age and stage distributions of the patients are shown, and the significance of the results is discussed.

N.B.T. TEST—FALSE-NEGATIVE AND FALSE-POSITIVE RESULTS

The Lancet ◽  
1972 ◽  
Vol 299 (7764) ◽  
pp. 1341-1342 ◽  
Author(s):  
RonaldP. Ng ◽  
T.K. Chan ◽  
D. Todd
Keyword(s):  
False Positive ◽  
False Negative ◽  
Positive Results

scholarly journals OVERVIEW OF MALARIA PARASITE AND ITS PREVENTION IN INDIA

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Adil Raza ◽  
Megha Chaudhary ◽  
Sonika Devi
Keyword(s):  
Red Blood Cells ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Malaria Parasite ◽  
Plasmodium Species ◽  
Peripheral Blood Smear ◽  
Infected Mosquito ◽  
Protozoan Parasites ◽  
Malaria Parasites ◽  
Genus Plasmodium

Background: Malaria is a systematic disease caused by a parasite called Plasmodium which is transmitted into the human blood via female Anopheles mosquito. Malaria in humans is caused by four species of protozoan parasites of the genus Plasmodium: P. falciparum, P. vivax, P. ovale, and P. malariae. The parasite enters the human body through a mosquito bite and travel to the very crucial organ, the liver, where they multiply and come back to the bloodstream and destroy red blood cells. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases it can cause yellow skin, seizures, coma, or death. Symptoms usually begin ten to fifteen days after being bitten by an infected mosquito. In those who have recently survived an infection, reinfection usually causes milder symptoms. Objectives: Isolation of different species of malaria parasites. The prevalence of malaria parasite in India. Methods: The procedure follows these steps: collection of peripheral blood, staining of smear with Leishman’s stain and examination of red blood cells for malaria parasites under the microscope. Results: We observed the plasmodium species in peripheral blood smear. Conclusion: Worldwide, the number of cases of malaria caused by Plasmodium falciparum, the most dangerous species of the parasite, is on the rise.

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