Gold Standard Test Research Articles

Antibiotic susceptibility of Pseudomonas aeruginosa in Saudi Arabia: a national antimicrobial resistance surveillance study.

Pseudomonas aeruginosa is a common pathogen causing healthcare-associated infections. Most surveillance studies from Saudi Arabia that assessed the resistance by P. aeruginosa were conducted in single centers or did not use broth microdilution (BMD), the gold standard test. This is the first national multicenter study to assess the resistance profiles of P. aeruginosa isolates in Saudi Arabia using BMD. Between 2022 and 2023, isolates from various infection sites were collected from seven hospitals in seven different regions of Saudi Arabia. The isolates were shipped to an academic microbiology lab, where their susceptibility was tested by BMD following Clinical Laboratory Standards Institute guidelines using Sensititre GNX3F plates. %Susceptibility to each antibiotic, and MIC50 and MIC90 were determined. In total, 185 P. aeruginosa isolates were collected. Most isolates came from respiratory specimens (34.1%), followed by urine (21.1%) and skin/soft tissue (17.8%). The highest susceptibility was to amikacin (76.8%). Concurrently, susceptibility to meropenem was 52%, but it was 43.8% to colistin. While all P. aeruginosa isolates met the definition of multidrug-resistance, 41 (22.2%) were difficult-to-treat and 10 (5.4%) were pandrug-resistant. Difficult-to-treat isolates made up 30.3% of skin and soft tissue isolates, 25.4% of respiratory isolates, 21.7% of blood isolates, and 17.9% of urine isolates. Pseudomonas aeruginosa demonstrated an unexpectedly high level of resistance to several commonly used antibiotics. Therefore, antimicrobial stewardship and infection control policies should be strictly enforced by hospitals across the country to optimize treatment, prevent the emergence and spread of resistant strains, and track resistance trends with local antibiograms.

Association between Antinuclear Antibodies Patterns and Immunological Markers with Systemic Lupus Erythematosus in Iraqi Female Patients

Background: Systemic lupus erythematosus is a condition where the immune system attacks various tissues and organs, affecting commonly women between the ages of 15 to 44. It is caused by genetics or environmental factors. A critical factor in the diagnosis by antinuclear antibodies at a level of ≥1:80. Objective: To assess the disease activity and identification of antinuclear antibody patterns and titer on Hep-2 cells with immunological markers. Methods: This was a case-control study conducted at Baghdad Teaching Hospital/Medical City between January 25, 2024, to April 25, 2024. 60 SLE patients were contrasted with 60 healthy controls. The American College of Rheumatology SLE criteria were used to make the diagnosis. Results: SLE patients had a mean age of 32.12±10.54 years, while controls had a mean age of 31.37±10.65 years (P=0.699). positive family history represents 15.0 % while negative family history of SLE patients is 85.0%. The mean disease duration was 5.25±4.77 years. The disease activity index (SLEDI) was (27.80 ±10.40). The most common patterns of Antinuclear Antibodies (ANA) are speckled (56.7%), homogeneous (26.7%), peripheral (1.7%), mixed (3.3%), and negative (11.7%) patterns. Conclusion: Antinuclear antibodies are considered the gold standard diagnostic test. A few healthy individuals display speckled patterns at a ratio of 1:40. The disease activity no significant with pattern.

Early prediction of gestational diabetes mellitus using first trimester maternal serum pregnancy-associated plasma protein-a: A cross-sectional study.

The oral glucose tolerance test with 75 g glucose is commonly regarded as the gold standard (GS) for the detection of gestational diabetes mellitus (GDM). However, one limitation of this test is its administration in the late second trimester of pregnancy in some countries (e.g., Iran). This study aimed to evaluate the accuracy of pregnancy-associated plasma protein-A (PAPP-A) for predicting GDM in the early first trimester of pregnancy using a novel statistical modeling technique. The study population consisted of 344 pregnant women who participated in the first trimester screening program for GDM. Maternal serum PAPP-A levels were measured between 11 and 13 gestational weeks for all participants. A Bayesian latent profile model (LPM) under the skew-t (ST) distribution was employed to estimate the diagnostic accuracy measures of PAPP-A in the absence of GS test outcomes. The mean (standard deviation) age of the participants was 28.87 ± 5.20 years. The median (interquartile range (IQR)) PAPP-A MoM was 0.91 (0.69-1.34). Utilizing the LPM under the ST distribution while adjusting for covariates, the sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of PAPP-A were 92% (95% credible interval [CrI]: 0.89, 0.98), 81% (95% CrI: 0.76, 0.91), and 0.91 (95% CrI: 0.83, 0.97), respectively. Notably, the pregnant women with GDM had significantly lower PAPP-A values ( -0.52, 95% CrI [-0.61, -0.46]). Generally, our findings confirmed that PAPP-A could serve as a potential screening tool for the identification of GDM in the early stages of pregnancy.

Harnessing the Power of Curcumin: Evaluating Its Efficacy as an Antileishmanial Agent in the Fight Against Leishmaniasis

Over 100 countries are impacted by the dangerous parasite disease leishmaniasis, which is categorized as a neglected tropical disease (NTD). Protozoan parasites use sandflies and other vectors to spread the disease. Herbal compounds like turmeric curcumin have demonstrated promise in the treatment of parasitic illnesses despite their limited bioavailability and water solubility. From small, self-healing skin lesions to serious intestinal infections, leishmaniasis can cause a wide range of illnesses in humans. Since there isn’t a gold standard test for one type, mucocutaneous leishmaniasis (MCL), it can be difficult to diagnose. Treatments for MCL can be quite harmful, which emphasizes how crucial a correct diagnosis. This study aims to assess the diagnostic performance of PCR (polymerase chain reaction) for MCL and to compare the findings with the authors’ most recent clinical research findings.

The 2023 European Task Force Criteria for Diagnosis of Arrhythmogenic Cardiomyopathy: Historical Background and Review of Main Changes.

Arrhythmogenic cardiomyopathy (ACM) is a cardiac disease featured by non-ischemic myocardial scarring linked to ventricular electrical instability. As there is no single gold-standard test, diagnosing ACM remains challenging and a combination of specific criteria is needed. The diagnostic criteria were first defined and widespread in 1994 and then revised in 2010, approaching and focusing primarily on right ventricular involvement without considering any kind of left ventricular variant or phenotype. Years later, in 2020, with the purpose of overcoming previous limitations, the Padua Criteria were introduced by an international expert report. The main novel elements were the introduction of specific criteria for left ventricular variants as well as the use of cardiac magnetic resonance for tissue characterization and scar detection. The last modifications and refinement of these criteria were published at the end of 2023 as the European Task Force criteria, by a "head-quarter" of ACM international experts, proving the emerging relevance of this condition besides its difficult diagnosis. In this review, emphasizing the progress in understanding the aetiology of the cardiomyopathy, an analysis of the new criteria is presented. The introduction of the term "scarring/arrhythmogenic cardiomyopathy" sets an important milestone in this field, underlying how non-ischemic myocardial scarring-typical of ACM-and arrhythmic susceptibility could be the main pillars of numerous different phenotypic variants regardless of etiology.

Congenital deafness and vestibular disorders: a systematic literature review.

Congenital deafness is a pathological entity that represents an economical and social burden, affecting up to 0.2% of newborns in Europe. Sensorineural hearing loss (SHL) is caused by a variety of factors, including congenital abnormalities, perinatal infectious diseases and genetic syndromes. The inner ear's vestibular system, nestled alongside the auditory organs, is crucial for balance maintenance. Its close connection with the auditory system means that disturbances in one often coincide with disturbances in the other, highlighting their intertwined functions. With this review we aim to describe objective vestibular tests found in literature and to study their use for diagnosis of vestibular disturbances in patients affected by congenital deafness. The review is conducted with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2020 guidelines. The search string used was: [(congenital deafness) OR (congenital hearing loss) OR (congenital hypoacusia)] AND [(vestibular disorders) OR (vertigo)]. An initial abstract reading selection was made, and a subsequent comprehensive full-text reading. For each article, we identified the type of vestibular test utilized and its corresponding outcome. Out of the initial-papers identified through the search string-articles met the eligibility criteria for further analysis through abstract and full-text reading. After further selection-articles were chosen for detailed examination, focusing on the data of patients. Congenital hearing loss profoundly affects a child's development, especially in language and communication skills, and it is frequently associated with a pathological vestibular system. Early identification allows timely intervention with personalized therapies. In current literature, there is still no gold standard test to identify balance disorders in patients with congenital hearing loss. There is considerable variability on the subject due to the inclusion of diverse patients with various diagnoses, alongside a wide range of available technologies. Managing such conditions necessitates collaboration among healthcare providers, ensuring comprehensive care through prompt diagnosis and personalized treatment plans. Ongoing research aims to further improve screening methods and develop precision medicine approaches tailored to individual needs.

Predicting Type 2 Diabetes Metabolic Phenotypes Using Continuous Glucose Monitoring and a Machine Learning Framework.

The study challenges the conventional classification of type 2 diabetes (T2D) and prediabetes based solely on glycemic levels. Instead, the results highlight the heterogeneity of underlying physiological processes that represent separate pathways to hyperglycemia. Individuals with normoglycemia and prediabetes can be classified according to the relative contribution of four distinct metabolic subphenotypes: insulin resistance, muscle and hepatic, β-cell dysfunction, and incretin defect, which comprise a single dominant or codominant physiologic process in all but 9% of individuals.Use of multiple time points during OGTT generates time-series data to better define the shape of the glucose curve: the application of a novel machine learning framework utilizing features derived from dynamic patterns in glucose time-series data demonstrates high predictive accuracy for identifying metabolic subphenotypes as measured by gold-standard tests in the clinical research unit. This method predicts insulin resistance, β-cell deficiency, and incretin defect better than currently-used estimates, with auROCs of 95%, 89%, and 88%, respectively.The muscle insulin resistance and β-cell deficiency prediction models above were validated with an independent cohort and then tested using glucose data series derived from OGTT performed at home with a continuous glucose monitor (auROC of at-home prediction of insulin resistance and β-cell deficiency is 88% and 84%, respectively). This approach offers a practical and scalable method for metabolic subphenotyping and risk stratification in individuals with normoglycemia or prediabetes, with potential to inform targeted treatments to prevent progression to T2D.

ThP8.12 - To do or not to do-Temporal artery Biopsy in Giant Cell arteritis

Abstract Aims Temporal artery biopsy (TAB) remains the gold-standard diagnostic test for giant cell arteritis (GCA). Our aim is to evaluate the correlation between initiation of corticosteroid therapy, timing of biopsy, and histological diagnosis of GCA through TAB. Moreover, analyse the usefulness of this practice. Methods Operative notes of TABs performed by a Vascular Surgery department at a teaching hospital between August 2021 and January 2023 were reviewed. We looked into the relationship between histological findings and the timing of corticosteroid treatment initiation prior to TAB. Results A total of eight patients had a TAB, with a male-to-female ratio of 2:6. The median age of the patients was 68-years-old (range 53-84). TABs were performed within 16 days of the referral (range 2-16). All were performed on elective theatre lists and none on emergency theatre lists (CEPOD). All patients had started corticosteroids by the time they had TAB, with a median duration of 11.5 days before TAB (range 2-16). The histopathology report was positive for active GCA in 1 case (12.5%) where the TAB was performed on day 3. In another performed on day 16, histopathology showed signs of healed inflammation (12.5%). In all other cases the report was negative (75%). All patients completed a full weaning course of steroids regardless of histological findings. Conclusion GCA is a systemic inflammatory vasculitis. Prompt initiation of high-dose corticosteroids is the mainstay management to reduce risks of ischaemic-related complications. Our work suggests the timing of biopsy is a key determinant of histological diagnosis of GCA.

Ultrasonographic Performance and Clinical Analysis of Ultrasound in the Diagnosis of Uterine Fibroids

Objective: To assess ultrasound’s ultrasonographic performance and clinical value in diagnosing uterine fibroids. Methods: 60 patients with suspected uterine fibroids admitted to the hospital between March 2021 and March 2024 were selected for this study. Abdominal B-mode ultrasound was used as the gold standard to detect pathological findings, and the results were compared and analyzed. Results: 54 patients were diagnosed after the gold standard, and the results of abdominal B-mode ultrasound were positive predictive value: 96.29%; negative predictive value: 66.67%; accuracy: 93.33%; sensitivity: 96.29%; specificity: 66.67%. Among 60 patients examined by B-mode ultrasound, there were a total of 54 patients who were diagnosed by the gold standard, and 19 cases of uterine leiomyosarcoma were confirmed by the detection of uterine leiomyosarcoma by the gold standard, and B-mode ultrasound (94.73%); 21 cases of cervical leiomyoma were confirmed by gold standard test and 20 cases of cervical leiomyoma were diagnosed by ultrasound (95.24%); 14 cases of mixed leiomyoma were confirmed by gold standard test and 14 cases of mixed leiomyoma were diagnosed by ultrasound (100.00%). Conclusion: Using abdominal ultrasound to examine patients with uterine fibroids can significantly improve the efficiency of diagnosis and treatment and provide a strong scientific basis for subsequent treatment decisions.

Lifestyle Profiling Using Wearables and Prediction of Glucose Metabolism in Individuals with Normoglycemia or Prediabetes.

This study examined the relationship between lifestyles (diet, sleep, and physical activity) and glucose responses at a personal level. 36 healthy adults in the Bay Area were monitored for their lifestyles and glucose levels using wearables and continuous glucose monitoring (NCT03919877). Gold-standard metabolic tests were conducted to phenotype metabolic characteristics. Through the lifestyle data (2,307 meals, 1,809 nights, and 2,447 days) and 231,206 CGM readings from metabolically-phenotyped individuals with normoglycemia or prediabetes, we found: 1) eating timing was associated with hyperglycemia, muscle insulin resistance (IR), and incretin dysfunction, whereas nutrient intakes were not; 2) timing of increased activity in muscle IS and IR participants was associated with differential benefits of glucose control; 3) Integrated ML models using lifestyle factors predicted distinct metabolic characteristics (muscle, adipose IR or incretin dysfunction). Our data indicate the differential impact of lifestyles on glucose regulation among individuals with different metabolic phenotypes, highlighting the value of personalized lifestyle modifications.

741P Comparison of the Idylla microsatellite instability (MSI) test with a gold standard MSI test and mismatch repair immunohistochemistry in endometrial cancer

741P Comparison of the Idylla microsatellite instability (MSI) test with a gold standard MSI test and mismatch repair immunohistochemistry in endometrial cancer

Correlation of Clinical and Electrophysiological Criteria in the Diagnosis of Guillain-Barré Syndrome: A Prospective Observational Study.

There are many criteria for diagnosing Guillain-Barré syndrome (GBS), and the yield of these diagnostic criteria varies. Each criterion requires some laboratory data and nerve conduction studies (NCS). Although supportive laboratory data are reassuring when present in suspected cases of GBS, when absent, they can potentially cause further delay in diagnosis and treatment. There is no gold standard test for the diagnosis of GBS, and there are multiple diagnostic criteria for GBS to date. The aim of the study is to know the sensitivity of different criteria, clinical and electrophysiological, for the diagnosis of GBS and to study the clinical spectrum and electrophysiological spectrum of GBS in our cohort of patients. We studied a total of 43 cases who presented with one or more of the following symptoms: relatively symmetrical and progressive flail-type weakness of more than one limb, with or without ataxia and/or ophthalmoplegia, and were diagnosed with GBS according to clinical criteria at the time of admission to Government Stanley Medical College Hospital. GBS mimics were ruled out. In all patients, the demographic data, cerebrospinal fluid (CSF) analysis (if done), and electrophysiological findings fitting into the diagnostic criteria of National Institute of Neurological Disorders and Stroke (NINDS), Dutch, and Brighton criteria were recorded. The need for assisted mechanical ventilation, neurology intensive care unit (NICU) stay, any complications, and treatment outcome details were recorded in a structured proforma. Most of the patients in our study were in their fourth decade of life, with a mean age of 41.37 years, similar to previous studies from India. Men are more frequently affected compared to women, similar to what has been observed in most studies done previously worldwide. In our study, electrophysiological criteria by Dutch criteria (87.5%), Brighton criteria (87.5%), and NINDS criteria (85.6%) had low sensitivity compared to the clinical criteria. In the present study, electrophysiological criteria proposed by the NINDS, Dutch, and Brighton criteria are less sensitive compared to clinical criteria in diagnosing GBS at early stages. Clinical criteria alone may be useful in resource-poor countries and at peripheral healthcare systems where NCS are not always readily available.

280. MANOMETRIC FINDINGS IN PATIENTS WITH GIANT HIATAL HERNIA: OESOPHAGEAL PHYSIOLOGY APPEARS TO IMPROVE WITH SURGERY

Abstract Background High resolution manometry (HRM) is a gold standard test of oesophageal physiology. The use of HRM in patients with giant hiatus hernia (GHH) is limited by historical technical challenges as well as unclear clinical implications of the findings. The aim of this study is to demonstrate feasibility of HRM in patients with GHH and study effect of surgery on oesophageal physiology of patients undergoing GHH repair. Methods Data was extracted from a prospectively populated database of patients with giant (>30% stomach above diaphragm) hiatus hernias. All patients that underwent HRM before and after surgery were included. Manometric findings before and after surgery were analysed and compared. Patient symptoms were correlated with manometric findings. Results Inclusion criteria were met by 30 patients: 83% female, average age 74 (range 51-86), 93% had type III hernia containing on average 55% of stomach. All operations but one were performed laparoscopically. Pre-operatively average LOS length was 1.89cm which improved significantly to 2.19cm after surgery (p<0.05). Nine patients had ineffective oesophageal motility on index study which normalised post operatively in 4 patients. Lower oesophageal sphincter integrated relaxation pressure (IRP) increased post-operatively from 9.07mmHg to 11.52mmHg (p<0.05). Distal contractility improved post-operatively, however this was not significant. Most common presenting symptoms were dyspnoea, anaemia, retrosternal pain, and dysphagia. There was no association between dysphagia and manometric findings before or after surgery. Conclusion This study provides an insight into HRM findings in patients with GHH before and after surgery. Majority of the physiological parameters improved with surgery. There was no correlation of symptom of dysphagia with manometric findings.

Exact interval estimation for three parameters subject to false positive misclassification

SummaryBinary data subject to one type of misclassification exist in various fields. It is collected in a double‐sampling scheme that includes a gold standard test and a fallible test. The main parameter of interest for this type of data is the positive probability of the gold standard test. Existing intervals are unreliable because the given nominal level is not achieved. In this paper, we construct an exact interval by inverting the E+M score tests and improve it by the general ‐function method. We find that the total length of the improved interval is shorter than the exact intervals that are also the improved intervals when we apply the ‐function to several existing approximate intervals, including the score and Bayesian intervals. Therefore, it is recommended for practice. We are also interested in two other parameters: —the difference between the two positive rates for the fallible and gold standard tests—and —the false positive rate for the fallible test. To the best of our knowledge, the research on these two parameters is limited. For , we find that any interval for can be converted to an interval for . So, the interval converted from the aforementioned recommended interval for is recommended for inferring . For , the improved interval by the ‐function method over the E+M score interval is derived. We use an example to illustrate how the intervals are computed and provide a real data analysis.

Clinical screening tool for early detection of congenital heart disease in children living at high altitude

Background: Congenital heart diseases (CHD) have a high morbidity and mortality and its early detection is critical. The aim of the study is to develop a clinical screening tool for early detection of children with congenital heart disease at high altitude. Methods: This was a hospital based cross sectional study. All children between age 0 to 1 year visiting the OPD and admitted in indoor services of pediatrics with suspected heart disease based on pre-defined clinical criteria were evaluated for development of clinical screening tool for prediction of presence of CHD using parameters; heart rate (HR), respiratory rate (RR), ratio of HR/RR, pulse oximetry, presence of precordial pulsations and murmurs. Then diagnostic performance of these tools was calculated by using ECHO as a gold standard test. Results: A total of 102 study participants were included in our study. Among the total, 79 (77.5%) had underlying CHD. Result was considered positive if any of them was pres ent. In children age less than one year living at high altitude suspected to have high risk for presence of CHD and/or arterial oxygen saturation of less than 87.2%, this screening tool has sensitivity of 78.79% and specificity of 66.67%. Conclusions: This study concluded that combination of screening tools along with pulse oximetry in the community settings of developing countries are better in early detection and timely management of CHD than using these tests/ parameters alone.

Gut microbiome profiles to exclude the diagnosis of hepatic encephalopathy in patients with cirrhosis

ABSTRACT Patients with cirrhosis who have cognitive complaints are presumed to have hepatic encephalopathy (HE), which leads to unwarranted medications while ignoring the underlying disease process causing these complaints. Since neuropsychological testing, the current gold standard for HE diagnosis, is not readily available, an orderable test is needed. We aimed to develop and validate a rapid gut microbiota test to exclude HE and determine stakeholder input on this approach. Stool was collected from two cohorts: a two-center training cohort (n = 305, on/not on HE-related therapy) and a multicenter validation cohort (n = 30, on HE treatment). Stool microbiota was analyzed rapidly using nanopore analysis. Stakeholder (patients and clinicians) needs assessment was evaluated using semi-quantitative questionnaires. In the training cohort, machine learning using neural network identified a 20-species signature that differentiated HE vs no-HE with 84% specificity compared to the gold standard neuropsychological testing. This high specificity persisted regardless of whether patients were on HE-related therapy or not. In the validation cohort, application of this profile led to reevaluation of the HE diagnosis and treatment in > 40% of the patients. This approach was acceptable to patients (Veterans in the validation cohort) and clinician (n = 40 nationwide) stakeholders. We conclude that a machine learning stool signature based on 20 microbial species developed in a training set and validated in a separate multicenter prospective cohort differentiated those with vs. without HE, identified patients misdiagnosed with HE, and was acceptable to patients and clinician stakeholders.

Comparative analysis of treponemal specific chemiluminescence test and rapid card test for screening of syphilis in blood donors – A tertiary center study

Abstract: BACKGROUND: Screening for transfusion-transmitted infections (TTIs) is an important step for the safety of blood transfusion. Major TTIs for which screening is done are hepatitis B surface antigen, antibody to hepatitis B virus, hepatitis C virus, human immunodeficiency virus, syphilis, and malaria. The aim of this study was to compare the diagnostic accuracy of treponemal-specific chemiluminescence test and rapid card test for the screening of syphilis by taking Treponema pallidum hemagglutination assay (TPHA) as a gold standard test. MATERIALS AND METHODS: This was a cross-sectional study. All the routine blood donors were screened according to the National Blood Transfusion Council guidelines. One hundred and twenty syphilis serology-positive samples were obtained either by rapid card test immunochromatographic test/chemiluminescence assay or both. These samples were further tested by TPHA (gold standard test). Statistical analysis was done using the Mcnemar test, DeLong et al. test, and Chi-square test P < 0.05 was considered statistically significant. RESULTS: The sensitivity and specificity of both chemiluminescence and rapid card test were comparable (P < 0.0001) and the diagnostic accuracy of chemiluminescence and rapid card test was 95.83% and 94.58%, respectively. CONCLUSION: Both chemiluminescence and rapid card tests show comparable performance, so it is concluded to use rapid card test as a reliable backup in remote areas, peripheral blood bank setup, and in emergency situations where timesaving is lifesaving.

Diagnostic value of antibody testing in comparison with lung scan and PCR in patients suspected of having COVID-19.

SARS-CoV-2 is a newly discovered viral infection. It's still unclear how antibodies react in infected individuals, and there is not enough evidence to support the clinical use of antibody examination. This study evaluates the diagnostic value of serologic tests for diagnosing COVID-19. 32 patients for whom serologic testing was performed within 7 to 21 days from symptom onset and whether they were diagnosed with COVID-19 by both PCR and lung HRCT as gold standard tests at the same time, were included in the study. Serologic tests (IgM / IgG) compared to PCR and lung HRCT scan to diagnose COVID-19, were 89.3% specific and 59.6% sensitive. Positive predictive value (PPV) was 95% and negative predictive value (NPV) was 37%. The diagnostic accuracy index of the serologic test was 0.745 (CI 0.651-0.838) (p-value <0.001). Serologic testing can be a complementary alternative for SARA-CoV-2 nucleic acid RT-PCR, although it cannot replace it completely. IgG/IgM combo test kits and RT-PCR together can give more insight into the diagnosis of SARS-CoV-2.

Diagnostic utility of the average peak LH levels measured during GnRH stimulation test.

Gonadotropin-releasing hormone (GnRH) test is the gold standard test to evaluate the hypothalamus-pituitary-gonadal (HPG) axis for the diagnosis of central precocious puberty (CPP). However, the diagnosis of cases with clinical features of CPP whilst have borderline peak luteinizing hormone (LH) remain challenges. We aimed to evaluate diagnostic performance of the average of LH levels measured during GnRH stimulation test. Cases with diagnosis of CPP and premature thelarche (PT) who had a GnRH stimulation test results were retrospectively reviewed. Anthropometric measurements (weight, height, and body mass index), age and sex-specific standard deviation scores, growth velocity, puberty stages, bone ages, serum FSH, LH, and estradiol levels were measured by electrochemiluminescence immunological method (ECLIA), and the GnRH stimulation test results, which performed by obtaining venous blood samples at basal, 20th, and 40th minutes for FSH and LH measurement, were recorded. A total of 76 girls (38 CPP, 38 PT) were included. We detected an average peak LH cut-off value of 4.25 IU/L with 94.7 % sensitivity and 97.4 % specificity, a 97.3 % positive predictive value, and a 94.9 % negative predictive value in GnRH test to differentiate cases with CPP from PT. This is the first study evaluating the diagnostic utility of the average of LH levels measured during GnRH stimulation test. We showed that the average of two LH measurements has a high diagnostic performance. Therefore, it can be used as a valid and reliable diagnostic tool for assessment of HPG axis activation, particularly for cases with a borderline peak LH level.

Assessment of accuracy of liver fluke diagnostic tests using the gold standard of total worm counts

In many regions of New Zealand liver fluke is endemic, infecting most grazing ruminants, including cattle, sheep, and deer. Restricting the economic losses and welfare costs associated with liver fluke relies on accurately identifying those animals with a production limiting infection. This has proven a difficult goal and although several antemortem quantitative tests are available, including faecal egg counts (FEC), serum ELISA and copro-antigen ELISA, none can be considered a gold standard test of liver fluke infection. The accepted gold standard test for fascioliasis is the total fluke count, which is both laborious and can only be completed at post-mortem. This study aimed to compare the performance of four liver fluke diagnostic tests, against the results of a gold standard total fluke count test. Two groups of cattle were selected, 29 culled mixed age beef cows (MAC) and ten 30-month-old steers. The cattle were blood sampled and faecal sampled prior to slaughter and their whole livers recovered post slaughter at the abattoir. Liveweight was also recorded at slaughter. After collection, each liver was weighed, scored for gross pathology, then serum, faeces and livers were frozen at −20 °C for later analysis. Faecal egg counts and F. hepatica copro-antigen ELISA tests were completed on the faecal samples and total fluke counts were completed on the livers. Fasciola hepatica antibody concentration in serum samples were quantified using a commercial ELISA test. Poisson regression models were built to model the association between each diagnostic test and the total fluke count, and a linear regression model was built to examine the relationship between each diagnostic test and live weight at slaughter.The median fluke count was significantly higher in MAC than steers (p = 0.01), and F. hepatica eggs were present in 100% steers and 66% MAC. There was a significant effect of copro-antigen ELISA value on total fluke count (p < 0.0001), with a coproantigen ELISA value = 20.1 predicting 10 flukes and a value = 44.8 predicting 30 flukes. There was also a significant effect of FEC on total fluke count (p = 0.002) but the R-squared value for this model was lower. There was no association between liver fibrosis score or antibody ELISA test and total fluke count (p = 0.95, p = 0.73, respectively). There was a significant effect of total fluke count (p = 0.03) on liveweight at slaughter, with liveweight falling 20.4 kg for each unit increase in loge (total fluke count). There was no effect of FEC (p = 0.11), antibody ELISA (p = 0.55) or copro-antigen ELISA value (p = 0.16) on liveweight at slaughter. Taken together, these results show that the coproantigen ELISA test is the better test for estimating the true liver fluke burden and that the number of flukes in the liver has a negative effect on cattle live weights at slaughter.