Nonradioactive Quantification of Low Concentrations of Hemoglobin a by HPLC for Midtrimester Prenatal Diagnosis of β-Thalassemia

1992 ◽  
Vol 38 (9) ◽  
pp. 1906-1908 ◽  
Author(s):  
R Maiavacca ◽  
S Tedeschi ◽  
A Mosca ◽  
S Calmi ◽  
P De Leonardis ◽  
...  
Keyword(s):  
Prenatal Diagnosis ◽  
Quantitative Data ◽  
Diagnostic Procedure ◽  
Complex Analysis ◽  
False Negative ◽  
Beta Thalassemia ◽  
Fetal Blood ◽  
Globin Chains ◽  
Low Concentrations ◽  
Positive Results

Abstract The usual methods for prenatal diagnosis of beta-thalassemia and other hemoglobinopathies by assay of fetal blood erythrocytes are either complex (analysis of globin chains synthesis by carboxymethylcellulose chromatography) or only semiquantitative [isoelectric focusing of hemoglobin (Hb)]. To further simplify the diagnostic procedure and to obtain quantitative data, we measured the small concentrations of Hb A in fetal erythrocytes by using a high-pressure liquid chromatography (HPLC) instrument (DIAMAT-TM; Bio-Rad) equipped with the new column proposed for measuring Hb A2. We analyzed 212 uncontaminated fetal blood samples obtained by cordocentesis between the 18th and 22nd weeks of pregnancy, using the HPLC procedure, and compared the results with those obtained by the above-named methods. The Hb A values obtained ranged between 0% and 8.5%; they were less than or equal to 1.8% in 44 fetuses affected by homozygous beta-thalassemia and greater than 2.5% in 168 unaffected fetuses. The method was simple, rapid, and reproducible (CV 3.2%) and there was good correlation between Hb A concentrations determined by HPLC and the beta/gamma ratio determined by carboxymethylcellulose chromatography (r = 0.7687; P less than 0.0001). No false-negative or false-positive results were observed, and there was no overlap of values between affected and unaffected fetuses.

scholarly journals Prenatal diagnosis of 4953 pregnant women with indications for genetic amniocentesis in Northeast China

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Rulin Dai ◽  
Yang Yu ◽  
Qi Xi ◽  
Xiaonan Hu ◽  
Haibo Zhu ◽  
...  
Keyword(s):  
Prenatal Diagnosis ◽  
Pregnant Women ◽  
Northeast China ◽  
Prenatal Screening ◽  
Chromosomal Abnormalities ◽  
False Negative ◽  
Screening Methods ◽  
Serological Screening ◽  
Diagnostic Center ◽  
Positive Results

Abstract Background Several different technologies are used for prenatal screening procedures and genetic diagnostic technologies. We aimed to investigate the rates of chromosomal abnormalities in cases with different abnormal prenatal indications and to determine the relationships between fetal chromosomal abnormalities and indicators of prenatal abnormalities in Northeast China. Methods We evaluated 4953 16- to 23-week singleton gestation cases using amniocentesis and a total of 3583 participants received serological screening. Fetal chromosomal analyses were performed for all samples using fluorescence in situ hybridization and karyotyping. Results Among these samples, 204 (4.12%) had fetal chromosomal abnormalities. A total of 3583 participants received serological screening, among whom 102 (2.85%) exhibited positive results. A total of 309 participants had ultrasonography; 42 (13.6%) of these had abnormalities. Among 97 participants who had non-invasive prenatal testing (NIPT), 59 (61%) had positive results. Among 1265 participants with advanced maternal age, 78 (6.2%) had abnormal results. Conclusion The serological screening and NIPT that were included in the prenatal screening methods all had false positive and false negative rates. Although they are both prenatal screening techniques, maternal serum screening cannot be replaced by NIPT. The pregnancy women should accept NIPT in a qualified prenatal diagnostic center. We recommend that pregnant women at high or critical risk undergoing prenatal screening should confirm the fetal karyotype through amniocentesis. Moreover, if women receive a positive result via NIPT, they should not have a pregnancy termination without undergoing further prenatal diagnosis.

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.

scholarly journals TO010A NEW IMMUN-TOXICOLOGICAL TEST TO DETECT POLYSULFONE HYPERSENSITIVITY IN HEMODIALYSIS PATIENTS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Joachim Beige ◽  
Ralph Wendt ◽  
Despina Rüssmann ◽  
Karl-Peter Ringel
Keyword(s):  
False Negative ◽  
False Negative Rate ◽  
Lymphocyte Transformation ◽  
Clinical Problem ◽  
Lymphocyte Transformation Test ◽  
Laboratory Research ◽  
Humoral Immune ◽  
Before And After ◽  
Positive Results

Abstract Background and Aims Incompatibility of dialysis procedure due to hypersensitivity against dialyzer material which currently is mainly based on polysulfone and derivatives can not be assessed by routine laboratory tests. Although the frequency of such symptoms is suspected to be low (below 2%) such resembles an important clinical problem because dialysis procedures are frequently accompanied by symptoms of non-tolerability with reasons not being entirely clear while circulatory reasons are suspected to play a major role. Method To enlighten the role of polysulfone hypersensitivity, we adapted known standardized material immune-toxicological tests (lymphocyte transformation test, basophil degranulation test) to the specific conditions of dialysis and polysulfone material sensitivity. We developed a method of polysulfone micronisation and measured humoral immune response of isolated patient´s lymphocytes when incubated with polysulfone dispersion. Results 39 samples from 103 patients with suspected polysulfone hypersensitivity showed positive results for type 1 (n=19), type 4 (n=18) or both type (n=2) reactions. There were no significant differences in the level of stimulation measured for DI, SI and lymphogenesis before and after dialysis (average delta -0.4; -0.28; - 1.74, p = 0.71; 0.34; 0.37) and with different dialyzer materials (Tab. 1). Patients with pos. type 4 results (LTT and lymphogenesis) showed highly correlated results in either LTT or lymphogenesis test (Fig. 1, R=0.87, p<0.0001). 8 out of 8 samples from patients with repeated test on different PS showed positive results on either PS. One patient tested positive on PS showed no hypersensitivity with another non-PS (PMMA) material. Conclusion This is the first methodological report showing plausible in-vitro results of patients samples concerning polysulfone intolerance. On the first superficial view, a “false-negative” rate of 60% looks rather disappointing, because all samples derived from patients with suspicion of PS hypersensitivity. However, due to the clinical variability of intolerance symptoms and the high prevalence of any problems after HD initiation, mainly of circulatory origin after initiating extracorporeal circuit, this rate may obviously express the true frequency of isolated PS material hypersensitivity in suspected patients. Alternative pathophysiological pathways of material sensitivity like complement activation, remain to be elucidated and incorporated into a comprehensive future testing panel. Further clinical and laboratory research is needed to define true polysulfone hypersensitivity and to enlighten the field of hypothetic subclinical material incompatibility in patients with impaired dialysis tolerability.

scholarly journals Diagnostic Performance of Ankle-Brachial Pressure Index in Lower Extremity Arterial Disease

2021 ◽  
Vol 07 (03) ◽  
pp. e132-e137
Author(s):  
Mohammed Alagha ◽  
Thomas M. Aherne ◽  
Ahmed Hassanin ◽  
Adeel S. Zafar ◽  
Doireann P. Joyce ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Sensitivity And Specificity ◽  
False Negative ◽  
Arterial Disease ◽  
Initial Assessment ◽  
Reference Standard ◽  
Lower Extremity Arterial Disease ◽  
Negative Results ◽  
Positive Results ◽  
Arterial Imaging

Abstract Introduction Ankle-brachial pressure indices (ABIs) continue to form the basis of diagnostics for lower extremity arterial disease (LEAD). However, there remains a paucity of data to support its accuracy. This study aims to evaluate its diagnostic sensitivity and specificity using established arterial-imaging modalities as a benchmark. Methods In this retrospective study, a regional, prospectively maintained, vascular laboratory database was interrogated to identify referred patients with arterial disease who underwent concomitant assessment with ABI and lower limb arterial duplex ultrasound (DUS). Duplex acted as the reference standard. Those who had peripheral computed tomography angiogram (CTA) within 3 months of initial assessment were included in a subgroup analysis to correlate ABI with CTA. The primary end point was the sensitivity and specificity of ABI compared with DUS as the reference standard. Results Concomitant assessment was performed in 438 limbs (250 patients) over a 27-month period. The ABI was normal (0.9 to 1.4) in 196 limbs (44.9%) and abnormal in the remaining 241 limbs (55.1%). False-positive results occurred in 83 out of 241 limbs (34.4%), and false-negative results occurred in 54 limbs out of 196 (27.5%). True-positive results were 158 out of 241 limbs (65.6%), whereas true-negative results were 142 out of 196 limbs (72.4%). ABI using DUS as a benchmark identified a sensitivity for peripheral artery disease of 72.3% and a specificity of 69.3%. Concomitant CTA imaging was available in 200 limbs. The sensitivity and specificity of ABI correlated with CTA were 65.5 and 68.8%, respectively. Conclusion ABIs have a moderate predictive value in the diagnosis of LEAD. Normal range outcomes cannot be taken to infer the absence of LEAD and, as such, further arterial imaging in the form of DUS or angiography should be strongly considered in those with suspected underlying disease requiring intervention. Further noninvasive tests such as exercise studies or pulse volume waveforms should be considered, if diagnostic uncertainty exists, in those requiring nonoperative intervention and risk factor control.

Magnetic resonance imaging versus ultrasonography for the in utero evaluation of central nervous system anomalies

2010 ◽  
Vol 6 (4) ◽  
pp. 340-345 ◽  
Author(s):  
Pierpaolo Peruzzi ◽  
Rebecca J. Corbitt ◽  
Corey Raffel
Keyword(s):  
Magnetic Resonance Imaging ◽  
Prenatal Diagnosis ◽  
Mr Imaging ◽  
False Negative ◽  
In Utero ◽  
Resonance Imaging ◽  
Fetal Ultrasonography ◽  
Negative Results ◽  
False Negative Results ◽  
Fetal Mr

Object The use of fetal MR imaging for the in utero evaluation of pathological conditions of the CNS is widely accepted as an adjunct to fetal ultrasonography studies. Magnetic resonance imaging is thought to characterize CNS anomalies better, and to provide a more exact diagnosis and accurate prognosis. The purpose of this study was to determine the role of and indications for fetal MR imaging in evaluating fetuses with different CNS abnormalities that were seen initially on prenatal sonograms. Methods Over a 3-year period, fetuses with prior sonographic evidence of CNS abnormalities who consequently received prenatal MR imaging at Columbus Nationwide Children's Hospital within 2 weeks of the fetal ultrasonography study were included in this study. For each patient, radiological reports from both studies were reviewed, analyzed, and compared with the findings at postnatal imaging or physical examination. Results of the 2 modalities were then compared in terms of diagnostic accuracy. Results Twenty-six fetuses were included in this study on the basis of an in utero sonogram showing a CNS anomaly. Their gestational age ranged from 17 to 35 weeks, with a mean of 25 weeks at the time of fetal ultrasonography. Hydrocephalus was identified in 16 fetuses, 6 had evidence of a spinal dysraphic defect, 2 had holoprosencephaly, 1 had an encephalocele, and 1 had multiple body abnormalities requiring detailed CNS evaluation. Twenty-five of the fetuses were correctly evaluated as having abnormal CNS findings on both fetal ultrasonography and fetal MR imaging. Fetal ultrasonography provided a correct prenatal diagnosis in 20 cases, whereas fetal MR imaging was correct in 22 cases. There were 9 cumulative false-positive results for fetal ultrasonography and 7 for fetal MR imaging, whereas for false-negative results there were a total of 34 and 19, respectively. Conclusions Fetal MR imaging is more sensitive in detecting fetal CNS abnormalities, but its ability to provide a correct prenatal diagnosis is only marginally superior to fetal ultrasonography. Moreover, fetal MR imaging is not exempt from misdiagnosis, and still shows a significantly high rate of false-negative results. Particularly for spinal dysraphic defects, fetal MR imaging does not seem to add important diagnostic or prognostic details when compared with fetal ultrasonography.

Modern Staging and Utility of PET Imaging in Esophageal Cancer Management

2008 ◽  
Vol 6 (9) ◽  
pp. 862-869 ◽  
Author(s):  
Kwang-Yu Chang ◽  
Jang-Yang Chang ◽  
Joseph Chao ◽  
Yun Yen
Keyword(s):  
Esophageal Cancer ◽  
Neoadjuvant Therapy ◽  
Imaging System ◽  
False Negative ◽  
Lymph Node Involvement ◽  
Cancer Management ◽  
Positron Emission ◽  
Node Involvement ◽  
Positive Results ◽  
Locoregional Lymph Node

Esophageal cancer is the eighth most common cancer worldwide, and one of the most fatal diseases despite modern medical treatment. Because correct staging and surveillance of neoadjuvant therapy for esophageal cancer is mandatory for further treatment planning, choosing a modern imaging system is important. The development of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) has provided alternate means of tumor detection distinct from more conventional methods. This modality has extraordinary performance in detecting locoregional lymph node involvement and distant metastatic disease, and has been introduced as a powerful tool in many guidelines. However, some factors still lead to false-negative or -positive results, raising questions of its accuracy. This article discusses the clinical efficacy of PET in staging and surveillance of neoadjuvant therapy in esophageal cancer, comparing its accuracy with conventional imaging modalities.

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.

scholarly journals Detection of a Thalassemic α-Chain Variant (Hemoglobin Groene Hart) by Reversed-Phase Liquid Chromatography

2008 ◽  
Vol 54 (6) ◽  
pp. 1053-1059 ◽  
Author(s):  
Isabelle Zanella-Cleon ◽  
Michel Becchi ◽  
Philippe Lacan ◽  
Piero C Giordano ◽  
Henri Wajcman ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Reversed Phase ◽  
Globin Chain ◽  
Reversed Phase Liquid Chromatography ◽  
Ionization Time ◽  
Globin Chains ◽  
Low Concentrations ◽  
Phase Liquid ◽  
Esi Mass Spectrometry ◽  
Hb Variant

Abstract Background: Hemoglobin (Hb) Groene Hart [α119 (H2)Pro→Ser (α1)], also known as Hb Bernalda, is a nondeletional α-thalassemic Hb variant that is frequent in southern Italy and North Africa. This variant is not supposed to be produced in the erythrocytes of carriers. The α-thalassemic behavior of this variant has been explained as an impaired interaction between the α-globin chain and the α-Hb–stabilizing protein. Methods: To separate globin chains, we developed a modified reversed-phase liquid chromatography (RPLC) procedure that uses acetonitrile–water solvents containing up to 3 mL/L trifluoroacetic acid. After RPLC, we characterized the isolated globin chains by electrospray ionization (ESI) mass spectrometry (MS) and analyzed their tryptic peptides with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS and nano-LC–ESI–MS/MS. Results: RPLC detected an abnormal peak with a retention time substantially greater than that of the wild-type αA-globin chain. We identified this variant as Hb Groene Hart and found it in the hemolysates of 11 unrelated patients (1 homozygote, 9 heterozygotes, and 1 heterozygote associated with the −α3.7 deletion). These patients possessed abnormal hematologic features suggesting an α-thalassemia phenotype. Molecular modeling suggested that the increase in hydrophobicity was due to opening of the GH interhelical segment following replacement of amino acid residue 119 with a nonhelix breaker residue. Conclusions: This method allows the detection of Hb variants at low concentrations, and adjusting the composition of the organic solvents enables the method to identify Hb variants with large changes in hydrophobicity.

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
Sign in / Sign up

Export Citation Format

Share Document