Diagnostic Value of Pleural Effusion Mononuclear Cells Count and Adenosine Deaminase for Tuberculous Pleurisy Patients in China: A Case-Control Study

A scoring model based on the pleural effusion adenosine deaminase-to-serum C-reactive protein ratio for differentiating tuberculous pleural effusion from non-tuberculous benign pleural effusion

BACKGROUND

Differentiating tuberculous pleural effusion (TPE) from non-tuberculous benign pleural effusion (non-TB BPE) can be challenging, especially in patients with low levels of pleural effusion adenosine deaminase (pADA) and negative etiological evidence. This study aimed to evaluate the diagnostic performance of the pADA to serum C-reactive protein ratio (pADA/sCRP) and to develop a scoring model for diagnosing TPE.

METHODS

This retrospective study included 364 patients with pleural effusion, comprising 121 with TPE and 243 with non-TB BPE from Peking Union Medical College Hospital. Clinical, laboratory, and imaging data were collected, and comparisons were made between the two groups. The diagnostic performance of the pADA/sCRP ratio and other statistically significant variables was assessed. Six valuable factors were selected for multivariate regression analysis to establish a predictive model, which was displayed as a nomogram.

RESULTS

The pADA/sCRP ratio demonstrated superior diagnostic performance compared to pADA alone, with an area under the curve (AUC), sensitivity, and specificity for identifying TPE of 0.68, 71%, and 64%, respectively. Six variables were selected to develop a nomogram, including night sweats, calcification on chest computed tomography, pleural effusion lymphocyte ratio, pADA/sCRP, hemoglobin, and neutrophil. With a cutoff value of 20 points, the AUC, sensitivity, and specificity for distinguishing TPE from non-TB BPE were 0.836, 83.4%, and 64.9%, respectively. The validation cohort confirmed the model with the AUC, sensitivity, and specificity of 0.815, 61.1%, and 82.4%, respectively.

CONCLUSION

The pADA/sCRP ratio exhibited improved diagnostic performance compared to pADA alone. The novel scoring system based on a nomogram demonstrated good diagnostic efficacy in differentiating TPE from non-TB BPE.

Diagnostic value of IFN-gamma in tuberculous pleural effusion

BACKGROUND

Simple, rapid, and accurate diagnosis of tuberculous pleural effusion (TPE) remains challenging. This study aimed to determine the accuracy of IFN-γ in diagnosing TPE.

METHODS

We quantified the expression of interferon-gamma (IFN-γ) in blood (B), adenosine deaminase (ADA), and IFN-γ in pleural effusions (PE) from 25 TPE patients and 31 non-TPE patients using a combination of immunological assays and flow cytometric analysis. The diagnostic performance of these three biomarkers was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

We found that IFN-γ levels in blood and pleural fluid were higher in the TPE group than in the non-TPE group. The mean concentration of IFN-γ in pleural fluid of the TPE group was 3140.90 (1817.94, 6611.05) pg/mL, while that of the non-TPE group was 4.91 (0.69, 8.6) pg/mL), and the difference was statistically significant (z = 6.39, P < 0.001). The mean blood IFN-γ was 40.19 (16.45, 59.08) pg/mL in the TPE group and 2.76 (1.96, 6.02) pg/mL in the non-TPE group, which was statistically different (z = 5.12, P < 0.001). The area under the ROC curve (AUC) for pleural fluid IFN-γ, blood IFN-γ, and ADA were 0.999 (95 % CI: 0.994-1.00), 0.901 (95 % CI: 0.798-1.00) and 0.996 (95 % CI: 0.987-1.00), respectively.

CONCLUSION

This study confirms that IFN-γ has high diagnostic validity in patients with TPE and can potentially be an excellent biomarker.

Biomarkers for distinguishing tuberculous pleural effusion from non-tuberculosis effusion: a retrospective study

BACKGROUND

Pleural effusion (PE) is a common clinical feature that presents a diagnostic challenge for clinicians. In this retrospective study, we aimed to assess the biomarkers, ratios, and multiple indicators in serum and Pleural effusion for the differential diagnosis of tuberculous pleural effusion (TPE) from non-tuberculosis effusion (non-TPE).

METHODS

The participants, who were divided into two groups: TPE and non-TPE (MPE and PPE), from Ningbo First Hospital, were incorporated in this study. The clinical and laboratory features were collected and analyzed using logistic regression analysis. Twelve biomarkers and their ratios in serum and PE were investigated for TPE versus non-TPE. Additionally, the value of multiple indicators for joint diagnosis was estimated.

RESULTS

Biomarkers and ratios showed good diagnostic performance. The five variables including Serum ADA, IGRA, Effusion ADA, Effusion ADA/Serum ADA and Effusion LDH/Effusion ADA were identified as valuable parameters for differential diagnosis of TPE from non-TPE. The combined diagnosis of the five indexes yielded the highest diagnostic accuracy for TPE with an AUC (0.919), sensitivity (90.30%), and specificity (94.50%).

CONCLUSIONS

The biomarkers and ratios demonstrated strong diagnostic performance, and the utilization of multiple indicators for joint diagnosis can improve the diagnostic efficacy of tuberculous pleurisy.

Development and validation of a prediction model to assess the probability of tuberculous pleural effusion in patients with unexplained pleural effusion

Differentiating tuberculous pleural effusion (TPE) from non-tuberculosis pleural effusion remains a challenge in clinical practice. This study aimed to develop and externally validate a novel prediction model using the peripheral blood tuberculous infection of T cells spot test (T-SPOT.TB) to assess the probability of TPE in patients with unexplained pleural effusion. Patients with pleural effusion and confirmed etiology were included in this study. A retrospective derivation population was used to develop and internally validate the predictive model. Clinical, radiological, and laboratory features were collected, and important predictors were selected using the least absolute shrinkage and selection operator. The prediction model, presented as a web calculator, was developed using multivariable logistic regression. The predictive performance of the model was evaluated for discrimination and calibration and verified in an independent validation population. The developed prediction model included age, positive T-SPOT.TB result, logarithm of the ratio of mononuclear cells to multiple nuclear cells in pleural effusion (lnRMMPE), and adenosine deaminase in pleural effusion ≥ 40 U/L. The model demonstrated good discrimination [with area under the curve of 0.837 and 0.903, respectively] and calibration (with a Brier score of 0.159 and 0.119, respectively) in both the derivation population and the validation population. Using a cutoff value of 60%, the sensitivity and specificity for identifying TPE were 70% and 88%, respectively, in the derivation population, and 77% and 92%, respectively, in the validation population. A novel predictive model based on T-SPOT.TB was developed and externally validated, demonstrating good diagnostic performance in identifying TPE.

Drug transdermal delivery by electrophonophoresis can increase the concentration of rifampicin in the pleural effusion of patients with tuberculous pleurisy but has no effect on the concentration of rifampicin in plasma

BACKGROUND

Electrophonophoresis (EP) has been widely used in various clinical fields. The purpose of this study was to evaluate the dermal permeability of rifampicin (RIF) in patients with tuberculous pleurisy assisted by EP and to verify the clinical application of this percutaneous drug delivery system in the treatment of tuberculous pleurisy, verify the system's influencing factors, and determine whether plasma drug concentration was increased.

METHOD

Patients were given oral isoniazid 0.3-0.4 g, rifampicin 0.45-0.60 g, pyrazinamide 1.0-1.5 g and ethambutol 0.75 g according to their body weight once a day. After 5 days of anti-tuberculosis treatment, 3 ml of rifampicin was delivered transdermally with EP. Pleural effusion and peripheral blood samples in patients were collected at and after dosing. The drug concentration in the samples was determined by high-performance liquid chromatography.

RESULT

The median plasma concentration (interquartile ranges) of RIF in 32 patients was 8.80 (6.65, 13.14) μg/ml before RIF transdermal injection plus EP and decreased to 8.09 (5.58, 11.82) μg/ml after 30 min of RIF transdermal injection plus EP. The RIF concentration in pleural effusion was higher than that before RIF-transdermal plus EP. In patients who received RIF via EP transdermal administration, the concentration of the drug at the local site was statistically higher than the concentration at the local site prior to penetration. However, no such enhancement was observed in plasma after transdermal administration of RIF.

CONCLUSION

EP can effectively increase the concentration of rifampicin in the pleural effusion of tuberculous pleurisy and has no effect on the circulating plasma concentration. The increased concentration of the drug in the lesion helps to destroy the bacteria.

Application of Adenosine Deaminase and γ-Interferon Release Assay in Pleural Fluid for the Diagnosis of Tuberculous Pleural Effusion in Patients Over 40 Years Old

Background

In patients with tuberculous pleural effusion (TPE) of various ages, the diagnostic accuracy of pleural biomarkers varies, and there are insufficient studies specifically in different age groups. Therefore, we investigated the adenosine deaminase cut-off value and its combination with the gamma interferon release assay for the diagnosis of TPE among patients aged ≥40 years.

Methods

A retrospective analysis of 198 patients who underwent medical thoracoscopy and were admitted to the hospital between 2015 and 2020 with exudative pleural effusion and either fever, night sweats, fatigue, cough, or other clinical manifestations was performed. The medical thoracoscopy, ADA, and T-SPOT results were analysed in the pleural fluid. The patients were divided into groups based on age: 18-39, 40-59, and 60-87.

Results

The best cut-off values of ADA were 29.5, 31.5 and 19.5 U/L, respectively, for the aged 18-39, aged 40-87 and aged 60-87 groups. The accuracy of 31.5 U/L was higher than 40 U/L for aged ≥40 years (86 vs 83%). The ADA diagnostic accuracy was higher than that of people under 40 years (83 vs 77%) when cut-off value of ADA was 40 U/L, but the IGRA accuracy was lower than that of people under 40 (87 vs 91%). The sensitivity of ADA or IGRA detection in patients over 40 years was 99%, and the specificity was 78%. The ADA specificity combined with IGRA for TPE was the highest (100%) in the ≥40 age group, and the sensitivity was 69%.

Conclusion

Our study revealed the best cut-off values of ADA for TBE in different age groups. Combining ADA and IGRA in pleural fluid improves the detection rate of TPE in patients over 40 years of age with exudative pleural effusion. ADA combined with IGRA increases specificity, and ADA or IGRA increases sensitivity substantially.

Development and validation of a prediction model for tuberculous pleural effusion: a large cohort study and external validation

Background

Distinguishing tuberculous pleural effusion (TPE) from non-tuberculosis (TB) benign pleural effusion (BPE) remains to be a challenge in clinical practice. The aim of the present study was to develop and validate a novel nomogram for diagnosing TPE.

Methods

In this retrospective analysis, a total of 909 consecutive patients with TPE and non-TB BPE from Ningbo First Hospital were divided into the training set and the internal validation set at a ratio of 7:3, respectively. The clinical and laboratory features were collected and analyzed by logistic regression analysis. A diagnostic model incorporating selected variables was developed and was externally validated in a cohort of 110 patients from another hospital.

Results

Six variables including age, effusion lymphocyte, effusion adenosine deaminase (ADA), effusion lactatedehy drogenase (LDH), effusion LDH/effusion ADA, and serum white blood cell (WBC) were identified as valuable parameters used for developing a nomogram. The nomogram showed a good diagnostic performance in the training set. A novel scoring system was then established based on the nomogram to distinguish TPE from non-TB BPE. The scoring system showed good diagnostic performance in the training set [area under the curve (AUC) (95% confidence interval (CI)), 0.937 (0.917–0.957); sensitivity, 89.0%, and specificity, 89.5%], the internal validation set [AUC (95%CI), 0.934 (0.902–0.966); sensitivity, 88.7%, and specificity, 90.3%], and the external validation set [(AUC (95%CI), 0.941 (0.891–0.991); sensitivity, 93.6%, and specificity, 87.5%)], respectively.

Conclusions

The study developed and validated a novel scoring system based on a nomogram originated from six clinical parameters. The novel scoring system showed a good diagnostic performance in distinguishing TPE from non-TB BPE and can be conveniently used in clinical settings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02051-4.

Diagnostic value and safety of medical thoracoscopy for pleural effusion of different causes

BACKGROUND

Pleural effusions occur for various reasons, and their diagnosis remains challenging despite the availability of different diagnostic modalities. Medical thoracoscopy (MT) can be used for both diagnostic and therapeutic purposes, especially in patients with undiagnosed pleural effusion.

AIM

To assess the diagnostic efficacy and safety of MT in patients with pleural effusion of different causes.

METHODS

Between January 1, 2012 and April 30, 2021, patients with pleural effusion underwent MT in the Department of Respiratory Medicine, The Second Affiliated Hospital of Xi'an Jiaotong University (Shaanxi, China). According to the discharge diagnosis, patients were divided into malignant pleural effusion (MPE), tuberculous pleural effusion (TBPE), and inflammatory pleural effusion (IPE) groups. General information, and tuberculosis- and effusion-related indices of the three groups were analyzed. The diagnostic yield, diagnostic accuracy, performance under thoracoscopy, and complications of patients were compared among the three groups. Then, the significant predictive factors for diagnosis between the MPE and TBPE groups were analyzed.

RESULTS

Of the 106 patients enrolled in this 10-year study, 67 were male and 39 female, with mean age of 57.1 ± 14.184 years. Among the 74 thoracoscopy-confirmed patients, 41 (38.7%) had MPE, 21 had (19.8%) TBPE, and 32 (30.2%) were undiagnosed. Overall diagnostic yield of MT was 69.8% (MPE: 75.9%, TBPE: 48.8%, and IPE: 75.0%, with diagnostic accuracies of 100%, 87.5%, and 75.0%, respectively). Under thoracoscopy, single or multiple pleural nodules were observed in 81.1% and pleural adhesions in 34.0% with pleural effusions. The most common complication was chest pain (41.5%), followed by chest tightness (11.3%) and fever (10.4%). Multivariate logistic regression analyses showed effusion appearance [odds ratio (OR): 0.001, 95%CI: 0.000-0.204; P = 0.010] and carcinoembryonic antigen (OR: 0.243, 95%CI: 0.081-0.728; P = 0.011) as significant for differentiating MPE and TBPE, with area under the receiver operating characteristic curve of 0.977 (95%CI: 0.953-1.000; P < 0.001).

CONCLUSION

MT is an effective, safe, and minimally invasive procedure with high diagnostic yield for pleural effusion of different causes.

Cardiac Expression of Esophageal Cancer-Related Gene-4 is Regulated by Sp1 and is a Potential Early Target of Doxorubicin-Induced Cardiotoxicity

Esophageal Cancer-Related Gene 4 (Ecrg4) expressed in cardiomyocytes and the cardiac conduction system is downregulated during cardiac ischemia and atrial fibrillation. To explore whether Ecrg4 plays any role in doxorubicin (DOX)-induced cardiotoxicity. Rats and neonatal rat cardiomyocytes (NRCMs) were employed to study the effect of DOX on Ecrg4 transcription. Bioinformatics combined with promoter analysis were used to map the rat Ecrg4 promoter. ChIP assay was used to evaluate the binding of Sp1 to the Ecrg4 promoter. Transient transfection was used to study the effect of Sp1 on the expression of endogenous Ecrg4. DOX decreased endogenous Ecrg4 gene expression in the heart and cultured NRCMs. In silico analysis showed that the 5'UTR immediately upstream of the start codon ATG, harbors a putative promoter that is GC-rich, and contains CpG islands, multiple overlapping Sp1sites. Transcription is initiated mainly on the 'C' at - 15. Serial 5'-deletion combined with dual-luciferase assays showed that the rat Ecrg4 core promoter resides at - 1/- 800. Sp1 transactivated Ecrg4 gene, which was almost abolished by DOX. Furthermore, ChIP assay showed that Sp1 specifically bound to the Ecrg4 promoter was interrupted by DOX. Finally, DOX suppressed Sp1 protein expression, and restoration of Sp1 increased Ecrg4 expression that was resistant to DOX-induced Ecrg4 downregulation. Importantly, cardiomyocyte-specific loss of Ecrg4 significantly enriched the differentially expressed proteins in the signaling pathways commonly involved in DOX-induced cardiotoxicity. Our results indicate that Sp1 mediates DOX-induced suppression of Ecrg4, which may contribute indirectly to its cardiotoxicity.

Diagnostic value of combined pleural interleukin-33, adenosine deaminase and peripheral blood tuberculosis T cell spot detection TB for tuberculous pleurisy

Background

To investigate the correlation between pleural fluid interleukin-33 (IL-33) and adenosine deaminase (ADA) and peripheral blood tuberculosis T cell spot detection (T-SPOT.TB), and the combined value of the three tests for the diagnosis of tuberculous pleurisy.

Methods

79 patients with pleural effusion admitted from June 2017 to December 2018 were enrolled. They were divided into tuberculous pleural effusion (TPE) group (57 cases, 72.2%) and malignant pleural effusion group (17 cases, 21.5%), pneumonia-like pleural effusion group (5 cases, 6.3%). Correlation between pleural fluid IL-33, pleural effusion ADA and peripheral blood T-SPOT.TB was analyzed, comparison of the three separate and combined diagnostic efficacy was also performed.

Results

The levels of IL-33, ADA and peripheral blood T-SPOT.TB in patients with TPE were significantly higher than those in non-TPE (P < 0.001). The level of pleural fluid IL-33 was positively correlated with pleural effusion ADA and peripheral blood T-SPOT.TB. The Area under the ROC curve (AUC) of TPE diagnosed by pleural IL-33, ADA and peripheral blood T-SPOT.TB were 0.753, 0.912 and 0.865, respectively. AUC for combined detection of pleural effusion IL-33, ADA and peripheral blood T-SPOT.TB is the largest, with a value of 0.962. Specificity is 100% and sensitivity is 88.5%.

Conclusion

Combined detection of pleural effusion IL-33, ADA and peripheral blood T-SPOT.TB can improve the diagnostic efficacy of tuberculous pleurisy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06575-w.

Biomarkers of Distinguishing Neutrophil-Predominant Tuberculous Pleural Effusion from Parapneumonic Pleural Effusion

BACKGROUND

Tuberculous pleural effusion (TPE) is usually characterized by lymphocytic predominance and high pleural fluid adenosine deaminase (pfADA), while parapneumonic pleural effusion (PPE) is usually characterized by neutrophilic predominance. However, in some cases, neutrophils can be predominant in TPE. In such cases, the differential diagnosis between TPE and PPE is challenging and has been rarely investigated. The aim of this study was to evaluate the accuracy of pfADA, pleural fluid lactate dehydrogenase (pfLDH) and other parameters, such as age/pfADA in the differential diagnosis of neutrophil-predominant TPE (NP-TPE) and PPE.

METHODS

Between January 2003 and August 2018, 19 patients with NP-TPE and 54 patients with PPE at Shanghai Jiao Tong University Affiliated Sixth People's Hospital were retrospectively reviewed. Age, blood and pleural fluid findings, and eight ratios that consisted of routine biomarkers were compared between the two groups in ≤50 and >50 years old groups. ROC curve analysis was used to evaluate diagnostic performance.

RESULTS

The three parameters with the largest AUC were age/pfADA, pfADA and pfLDH in ≤ 50 years old group, and pfADA, age/pfADA and the percentage of neutrophils in pleural fluid (pfN%) in >50 years old group. For patients ≤ 50 years old, pfADA combined with pfLDH or age/pfADA combined with pfLDH could increase the specificity to 100%, while the sensitivity of the former was high (84.6% vs 76.9%). For patients >50 years old, both pfADA combined with pfN% and age/pfADA combined with pfN% could increase the specificity to 90.3% with the same sensitivity.

CONCLUSIONS

Although pfADA played an important role in the discrimination of NP-TPE from PPE, combining pfADA with pfLDH for patients ≤50 years old or combining pfADA with pfN% for patients >50 years old might improve diagnostic performance.

Diagnostic Accuracy of Pleural Effusion Mononuclear Cells/Leukocyte Ratio in Tuberculous Pleurisy

Background: Tuberculous pleurisy (TBP) is a common clinical type of tuberculosis (TB) in China. TBP is difficult to diagnose. Whether the mononuclear cell/leukocyte (MNC/LEU) ratio in pleural effusion can contribute to accurate TBP diagnosis remains yet unclear.

Objective: To explore the diagnostic value of MNC/LEU ratio in pleural effusion for TBP in China.

Methods: This study was a retrospective case-control study involving 406 patients with pleural effusion of unknown cause who were hospitalized at the Henan Provincial People's Hospital. Using histopathological examination of thoracoscopic pleural biopsy as the gold standard for TBP diagnosis, a final total of 215 subjects were included in this study including 91 cases of TBP and 124 cases of non-TBP. The receiver operating characteristic (ROC) curve of pleural effusion MNC/LEU ratio for TBP diagnosis was plotted and the area under curve (AUC) and the optimal cutoff value were determined. In addition, the sensitivity, specificity and accuracy of the MNC/LEU ratio at the optimal cutoff value for TBP diagnosis were also evaluated.

Results: The MNC/LEU ratio was significantly higher in TB pleural effusion [95.9% (89.7–98.0%)] than in non-TB pleural effusion [77.8% (39.3–93.2%)] (P < 0.001). The AUC was 0.776 (95% CI, 0.714–0.830), and the sensitivity, specificity and accuracy for TBP diagnosis at the 93.7% cutoff value were 64.83%, 79.03%, and 0.730, respectively.

Conclusion: The pleural effusion MNC/LEU ratio may be a new and valuable laboratory indicator for the diagnosis of tuberculous pleurisy in China.

Role of cancer ratio and other new parameters in the differential diagnosis of malignant pleural effusion

OBJECTIVES

We compared the diagnostic potential of cancer ratio (CR, serum lactate dehydrogenase [LDH]/pleural fluid adenosine deaminase [pfADA]), cancer ratio plus (CR plus, cancer ratio/pleural lymphocyte percentage), and age/pfADA ratio with pfADA in malignant pleural effusion.

METHODS

Data from 100 patients with malignant pleural effusion (MPE) and 119 patients with tuberculous pleural effusion (TPE) were retrospectively collected. PfADA, age/pfADA ratio, CR, and CR plus were compared between patients with MPE and those with TPE in two age groups (≤50 and >50 years). The best cut-off value was determined, and the diagnostic performance was evaluated according to the receiver operating characteristic curve.

RESULTS

PfADA was statistically significantly lower while age/pfADA ratio, CR, and CR plus were significantly higher in the MPE group than in the TPE group in both age groups (p<0.05). For patients aged ≤50 years, the differential diagnostic value of pfADA for MPE was better than those of age/pfADA ratio, CR, and CR plus. At a cut-off value of 13.0 U/L, the sensitivity, specificity, and accuracy were 88.9%, 100.0%, and 98.9%, respectively. For patients aged >50 years, the diagnostic performance of CR plus was superior to those of pfADA, age/pfADA ratio, and CR. At a cut-off value of 22.6, the sensitivity, specificity, and accuracy of CR plus for the diagnosis of MPE were 86.8%, 84.6%, and 86.2%, respectively.

CONCLUSIONS

The best parameter for diagnosing MPE was different for patients aged ≤50 years and >50 years. For patients aged >50 years, CR plus was a good parameter for the differential diagnosis of MPE. For patients aged ≤50 years, pfADA was better.

The roles of adenosine deaminase in autoimmune diseases

Autoimmune diseases patients are characterized by the autoimmune disorders, whose immune system can't distinguish between auto- and foreign- antigens. Thus, Immune homeostasis disorder is the key factor for autoimmune diseases development. Adenosine deaminase (ADA) is the degrading enzyme for an immunosuppressive signal - adenosine, and play an important role in immune homeostasis regulation. Increasing evidences have shown that ADA is involved in various autoimmune diseases. ADA activity were changed in multiple autoimmune diseases patients and could be served as a biomarker for clinical diagnosis. In this study, we analyze the change of ADA activity in patients with autoimmune diseases, and we underline its potential diagnostic value for autoimmune diseases patients.

Preoperative COVID-19 testing for elective vitreoretinal surgeries: Experience from a major tertiary care institute in South India

PURPOSE

To study the prevalence of asymptomatic SARS-CoV-2 virus infection (COVID-19) among patients undergoing elective vitreoretinal surgeries at a tertiary care eye hospital.

METHODS

This cross-sectional, observational study was performed between July 16, 2020 and August 31, 2020, in the retina clinic of a tertiary care eye hospital in south India. All patients undergoing elective retinal surgical procedures underwent RT-PCR testing for SARS-CoV-2 before being posted for surgery and after obtaining informed consent. Patients planned for surgery under general anesthesia underwent additional computed tomography of the chest. Testing strategies and outcomes were documented.

RESULTS

Out of a total of 413 patients who were given appointments for surgery during this period, nine patients (2.2%) were found to have positive RT-PCR for SARS-CoV-2, and their surgeries were postponed. The test positivity (prevalence) rate of asymptomatic COVID-19 infection among all elective vitreoretinal surgical patients in our hospital was 2.2%. None of the patients were symptomatic for COVID-19.

CONCLUSION

Our results showed that among patients visiting high volume ophthalmic centers in the near future, approximately 1 in 45 patients may be asymptomatic, SARS-CoV-2 RT-PCR positive. Asymptomatic COVID-19 patients may lead to chances of transmission of the virus inside healthcare facilities among other visiting patients and healthcare workers.