Optimising the utility of pleural fluid adenosine deaminase for the diagnosis of tuberculous pleural effusion

Abstract

Introduction: Pleural fluid adenosine deaminase (pfADA) is a simple, rapid and inexpensive surrogate marker for tuberculous pleural effusion (TPE). A nationwide cut-off of 40 U/L is currently used based on overseas data. There is a need to optimise the diagnostic utility of pfADA by establishing a local cut-off value. In this study, we aimed to describe the demographics and clinical characteristics of patients with TPE and non-TPE; determine the sensitivity and specificity of current pfADA of 40 U/L; and establish a new local pfADA cut-off for TPE. Methods: We conducted a single-centre, observational, prospective study of patients with exudative pleural effusion and pfADA measured from 1 October 2019 to 30 April 2020 at Queen Elizabeth Hospital, Malaysia. Results: The diagnosis of analysed patients ( n = 93) included TPE ( n = 41), malignancy ( n = 28), parapneumonic effusion ( n = 12) and other causes ( n = 12). The mean pfADA was 51.15 U/L (standard deviation (SD) = 13.77) among TPE group and 18.86 U/L (SD = 12.33) among non-TPE. When analysis was restricted to TPE patients, the local pfADA cut-off is 29.6 U/L, with a sensitivity of 97.6% and specificity of 90.4%. The current pfADA of 40 U/L has a sensitivity of 87.8% and specificity of 92.3%. Conclusion: We established a local pfADA cut-off of 29.6 U/L for TPE. Optimising the utility of pfADA helps to enhance clinicians’ treatment confidence of TPE when initial work-up is inconclusive.

Diagnostic Accuracy of Lactate Dehydrogenase/Adenosine Deaminase Ratio in Differentiating Tuberculous and Parapneumonic Effusions: A Systematic Review

“…However, TPE and parapneumonic effusion (PPE) are often difficult to differentiate owing to the overlapping clinical features. Owing to the low sensitivity of fluid mycobacterial culture and medical thoracoscopy not being universally available, biomarkers such as adenosine deaminase (ADA) are often employed as rule-out tools [ 3 ]. However, further complicating matters, PPE and TPE often present with elevated ADA [ 3 ].…”

“…Owing to the low sensitivity of fluid mycobacterial culture and medical thoracoscopy not being universally available, biomarkers such as adenosine deaminase (ADA) are often employed as rule-out tools [ 3 ]. However, further complicating matters, PPE and TPE often present with elevated ADA [ 3 ]. ADA may be raised in bacterial empyema as well, thus making it difficult to differentiate it from tuberculous empyema [ 4 ].…”

Adenosine Deaminase Diagnosed T.B Pleuritis- Embracing the “New” Modality of Diagnosis in Resource Limited Ugandan Settings.

“…The test is simple, affordable, rapid and minimally invasive (LIGHT, 2010). ADA levels greater or equal to 40 IU/L are associated with a sensitivity of 87.8 to 97.6% and specificity of 90.4 to 92.4 % (Huan et al , 2021). However, in low and middle income settings the test hasn't been embraced because of laboratory inadequacies and lack of knowledge about it, and fear of false positives, majorly malignancy, empyema, Para-pneumonic, collagen diseases, (Valdés et al , 1993) and rheumatoid pleuritis (Hooper, Lee and Maskell, 2010).…”