Simple modifications of three routine in vitro tests of thyroid function.

1976 ◽  
Vol 22 (10) ◽  
pp. 1715-1718 ◽  
Author(s):  
R W Pain
Keyword(s):  
Diagnostic Accuracy ◽  
Thyroid Function ◽  
False Positive ◽  
Reference Range ◽  
False Negative ◽  
Work Load ◽  
In Vitro Tests ◽  
Free Thyroxine Index ◽  
Total Thyroxine

Abstract Semi-automation of equipment and simple modifications of technique reduced the work load without loss of diagnostic accuracy for three commonly used in vitro tests of thyroid function (total thyroxine, thyrobinding index, and free thyroxine index). Major innovations were the use of serum standards for all tests and having each duplicate for tests performed by a different technician. Attention is drawn to the false-positive and false-negative errors that occur when the 95% euthyroid limits is the sole reference range used.

Pictorial reporting of multiple thyroid function results.

1976 ◽  
Vol 22 (10) ◽  
pp. 1562-1566
Author(s):  
R W Pain ◽  
B M Duncan
Keyword(s):  
Thyroid Function ◽  
Reporting System ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Testing Procedures ◽  
Function Tests ◽  
Free Thyroxine Index ◽  
Total Thyroxine ◽  
Experience Difficulty

Abstract Clinicians experience difficulty in correctly interpreting the results of in vitro thyroid function tests in the presence of abnormalities of thyrobinding proteins or when results are borderline. This difficulty has been largely resolved in our laboratory by three innovations. First, the borderline areas for each of three routine tests of thyroid function (total thyroxine, thyrobinding index, and free thyroxine index) were accurately determined. Second, the results from this routine profile of three tests were displayed pictorially so as to produce patterns characteristic of various diagnostic situations, including euthyroidism in the presence of abnormalities of thyrobinding proteins. Third, interpretive comments and, in the case of borderline patterns, suggested further testing procedures were added to the report. Clinicians find the reporting system helpful and respond when additional tests are suggested. The system, operated manually at first, was later computerized.

Investigation of the Free and Total Thyroxine-binding Capacity of Plasma Proteins in Thyroid Disorders

1971 ◽  
Vol 10 (04) ◽  
pp. 299-304
Author(s):  
József Takó ◽  
János Fischer ◽  
Jusztina Juhász ◽  
Ilona Sztraka ◽  
István Kapus ◽  
...  
Keyword(s):  
Blood Cell ◽  
Thyroid Function ◽  
Oral Contraceptives ◽  
Red Blood Cell ◽  
Plasma Proteins ◽  
Binding Capacity ◽  
Thyroid Disorders ◽  
Thyroid Function Tests ◽  
Total Thyroxine

SummaryThe results of thyroid function tests have been compared with data on the thyroxine-binding capacity of plasma proteins in hyper-, hypo- and euthyroid cases, the latter including women taking oral contraceptives (Infecundin). It was found that there exists a significant correlation of exponential nature between the in vitro red blood cell 125I-triiodothyronine uptake (RCU) and the free thyroxine-binding capacity of the thyroxine-inding globulin (TBG).

In Vitro Tests of Thyroid Function in Pregnancy

1976 ◽  
Vol 1 (5) ◽  
pp. 206-210
Author(s):  
MARTIN L. NUSYNOWITZ ◽  
STEPHEN PLYMATE ◽  
JERRY L. PRATHER
Keyword(s):  
Thyroid Function ◽  
In Vitro Tests ◽  
In Pregnancy

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.

scholarly journals Causes of misdiagnoses by thyroid fine-needle aspiration cytology (FNAC): our experience and a systematic review

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Yanli Zhu ◽  
Yuntao Song ◽  
Guohui Xu ◽  
Zhihui Fan ◽  
Wenhao Ren
Keyword(s):  
Systematic Review ◽  
Diagnostic Accuracy ◽  
Predictive Value ◽  
False Positive ◽  
False Negative ◽  
Diagnostic Errors ◽  
Published Data ◽  
Cystic Lesions ◽  
Adenomatous Hyperplasia ◽  
Sensitivity Specificity

Abstract Objective FNA is a simple, safe, cost-effective and accurate diagnostic tool for the initial screening of patients with thyroid nodules. The aims of this study were to determine the diagnostic utility of FNAC performed in our institution, assess the cytomorphologic features that contribute to diagnostic errors and propose improvement measures. Methods A total of 2781 FNACs were included in the study, and 1122 cases were compared with their histological diagnoses. We retrospectively reexamined our discordant (both false-negative and false-positive) cases and performed a systematic review of previous studies on causes of misdiagnoses. Results When DC V and DC VI were both considered cytologic-positive, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy were 98.3, 30.9, 94.9, 58.3 and 93.5%, respectively. If DC VI was considered cytologic-positive, the sensitivity, specificity, PPV, NPV and diagnostic accuracy of FNAC were 98.0, 84.0, 99.4, 58.3, and 97.5% respectively. The main cause of false-negative diagnoses was sampling error (13/15, 86.7%), while interpretation error led to the majority of the false-positive diagnoses (38/47, 80.9%). Overlapping cytological features in adenomatous hyperplasia, thyroiditis and cystic lesions were the major factors contributing to interpretation errors, while the size and number of nodules may have led to false-negative diagnoses because of heterogeneity and unsampled areas. Conclusions The sensitivity and PPV of thyroid FNAC in our institution were higher than those in the published data, while the specificity and NPV were lower. Regarding the FNA category DC V, a frozen section analysis during diagnostic lobectomy is necessary. Multiple passes should be performed in various parts of a large nodule or from different nodules to reduce the risk of false-negative findings. Cytopathologists should strengthen their criteria for the identification of adenomatous hyperplasia, thyroiditis and cystic lesions to avoid false-positive diagnoses. NIFTP has little effect on diagnostic accuracy and the distribution of diagnostic errors.

811 WHETHER 10 WATER SWALLOWS NECESSARY TO OBTAIN REPRODUCIBLE RESULTS OF HIGH-RESOLUTION OESOPHAGEAL MANOMETRY?

2021 ◽  
Vol 34 (Supplement_1) ◽  
Author(s):  
Sergey Morozov ◽  
Vasily Kropochev ◽  
Alexey Artemov
Keyword(s):  
High Resolution ◽  
Diagnostic Accuracy ◽  
False Positive ◽  
Roc Analysis ◽  
Characteristic Curve ◽  
False Negative ◽  
Ratio Test ◽  
Type I ◽  
Primary Position ◽  
Oesophageal Manometry

Abstract   Not less than ten wet swallows assessment in the primary test position is recommended by Chicago classification 4.0 for high-resolution oesophageal manometry (HREM); however, the required number of measurements are not sufficiently supported. Aim to evaluate the number of wet swallows necessary for correct interpretation of the results of lower esophageal sphincter integrated relaxation pressure (IRP) with low probability of type I and II errors. Methods Patients referred to perform HREM were enrolled. Solid-state 10Fr catheter and Solar (Laborie) software were used. Minimum 10 swallows by 5 mL water were obtained. These were analysed for cumulative means of IRP after 1…9 measurements. Conclusion made at each moment was compared with one based on 10 measurements. The results were characterized as true/false positive/negative for calculation of diagnostic accuracy. To exclude sample influence, Monte-Carlo simulation of sequential decision-making was performed with the use of sequential probability ratio test. Association of the diagnostic accuracy from recall was studied with the use of receiver operating characteristic curve (ROC) analysis. Results One hundred subjects were enrolled (25 with disorders of EGJ outflow). During the simulation, the probability of matching the decisions based on the 10 measurements and lower number of them was high. ROC analysis showed that actual probability to obtain false-positive results was twice as lower then ‘allowed’ rate of 5%. The probability to make false-negative results did not exceed 10% in any number of measurements. The probability that the conclusions made after 2 and after 10 measurements match was 0.9584 in those with disorders of EGJ outflow and 0.9652 in those without (figure 1). Conclusion The standard number of measurements required to support the presence of disorders of EGJ outflow during evaluation of 5 mL wet swallows in the primary position is excessive. Values of the IRP after 2 swallows allows to make similar decision to that after 10 swallows with >95% probability. This allows to reduce the number of wet swallows to assess in the primary position and save time for assessments in alternative position or perform provocation tests.

Danger of false negative (exclusion) or false positive (diagnosis) for ‘congenital thrombophilia’ in the age of anticoagulants

2019 ◽  
Vol 57 (6) ◽  
pp. 873-882 ◽  
Author(s):  
Emmanuel J. Favaloro
Keyword(s):  
False Positive ◽  
Ex Vivo ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
False Negative ◽  
Factor V Leiden ◽  
Protein S ◽  
Factor V ◽  
Increased Risk

Abstract Background Most guidelines and experts recommend against performance of thrombophilia testing in general, and specifically against testing patients on pharmacological anticoagulants, due to substantially increased risk of false positive identification. For example, vitamin K antagonist (VKA) therapy affects protein C (PC) and protein S (PS), as well as some clotting assays (e.g. as used to investigate activated PC resistance [APCR]). Although heparin may also affect clotting assays, most commercial methods contain neutralisers to make them ‘insensitive’ to therapeutic levels. Direct oral anticoagulants (DOACs) also affect a wide variety of thrombophilia assays, although most reported data has employed artificial in vitro spiked samples. Methods In the current report, data from our facility for the past 2.5 years has been assessed for all ‘congenital thrombophilia’ related tests, as evaluated against patient anticoagulant status. We processed 10,571 ‘thrombophilia’ related test requests, including antithrombin (AT; n=3470), PC (n=3569), PS (n=3585), APCR (n=2359), factor V Leiden (FVL; n=2659), and prothrombin gene mutation (PGM; n=2103). Results As expected, VKA therapy affected PC and PS, and despite manufacturer claims, also APCR. Most assays, as suggested by manufacturers, were largely resistant to heparin therapy. DOACs’ use was associated with falsely low APCR ratios (i.e. FVL-like effect) and somewhat unexpectedly, anti-Xa agents apixaban and rivaroxaban were also associated with lower AT and higher PS values. Conclusions It is concluded that ex-vivo data appears to confirm the potential for both false positive and false negative ‘thrombophilia’ events in patients on anticoagulant (including DOAC) treatment.

Methylene Blue as a Diagnosis and Screening Tool for Oral Cancer and Precancer

2020 ◽  
pp. 019459982094768
Author(s):  
Se Hwan Hwang ◽  
Sung Won Kim ◽  
Eun A. Song ◽  
Junuk Lee ◽  
Do Hyun Kim
Keyword(s):  
Methylene Blue ◽  
Oral Cancer ◽  
Diagnostic Accuracy ◽  
False Positive ◽  
Characteristic Curve ◽  
False Positive Rate ◽  
False Negative ◽  
High Sensitivity ◽  
Summary Receiver Operating Characteristic ◽  
True Negative

Objectives To evaluate the accuracy of methylene blue (MB) for diagnosing oral cancer and precancer. Data Sources PubMed, Cochrane Database, Embase, Web of Science, SCOPUS, and Google Scholar. Review Methods Two authors working independently reviewed 6 databases from their dates of inception until April 2020. Studies exploring oral mucosal disorders as detected by MB were assessed. True-positive, true-negative, false-positive, and false-negative data were extracted for each study. Methodological quality was evaluated with the Quality Assessment of Diagnostic Accuracy Studies tool (v 2). Results Seven prospective and retrospective studies (N = 493) were included. The diagnostic odds ratio of MB was 20.017 (95% CI, 10.65-37.63, I2 = 23%). The area under the summary receiver operating characteristic curve was 0.699. Sensitivity was 0.903 (95% CI, 0.84-0.94, I2 = 54%), and specificity was 0.68 (95% CI, 0.60-0.75, I2 = 0%). The correlation between the sensitivity and the false-positive rate was –0.17, indicating an absence of heterogeneity. Conclusions Regarding diagnostic accuracy, MB had high sensitivity but low specificity, suggesting that it cannot be recommended as a replacement for the currently used standard of a scalpel biopsy with histologic assessment. Instead, it should be used as an adjunct to conventional assessment because of its low toxicity and price.

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