An observational study in Pleural Effusion and Chronic Kidney Disease, sponsored by Assiut University. Not yet recruiting. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-04-23.
Sponsored by Assiut University · Observational
The purpose of this observational study is to understand the causes of pleural effusion (a buildup of fluid around the lungs) in patients with advanced Chronic Kidney Disease (CKD Stages 3 to 5). Pleural effusion is a common complication in kidney disease, but it can be caused by many different issues, such as simple fluid overload, heart failure, or infections like tuberculosis.
To treat this fluid buildup effectively, doctors need to classify whether the fluid is a transudate (usually caused by pressure imbalances like fluid overload) or an exudate (caused by inflammation, lung disease, or infection). Standard medical formulas, known as Light's Criteria, are typically used to figure this out by comparing proteins in the fluid to proteins in the blood. However, these standard tests may sometimes misclassify the fluid in kidney disease patients because their baseline blood protein and albumin levels are often altered by their condition.
Researchers in this study will enroll adult CKD patients (both on dialysis and not yet on dialysis) who have confirmed fluid around their lungs. Participants will undergo a standard, ultrasound-guided procedure called a diagnostic thoracentesis to safely draw a small amount of the chest fluid. At the same time, a routine blood sample will be taken.
The study aims to:
Chronic kidney disease (CKD) is a major global health burden. As CKD progresses through stages III-V, systemic complications become increasingly prevalent, with pleural effusion identified in 20-40% of CKD patients at autopsy. Pleural effusion in CKD arises from diverse mechanisms. Transudative effusions are predominantly associated with fluid overload and heart failure. Exudative effusions are most commonly caused by tuberculosis, uremic pleuritis, and parapneumonic processes.
The cornerstone of differentiating transudative from exudative pleural effusions remains Light's Criteria. However, the criteria carry an acknowledged risk of misclassification in CKD patients, where altered protein metabolism, reduced serum albumin, and dialysis-related biochemical shifts may distort pleural fluid-serum ratios. Given the diagnostic complexity posed by coexisting comorbidities, there is a clear need for a dedicated prospective study that systematically evaluates the incidence, etiology, and biochemical classification of pleural effusions in CKD Stage 3-5 patients.
Eligible participants will undergo a comprehensive clinical evaluation, which includes a structured clinical history form to capture demographic data, presenting symptoms, CKD history, dialysis status, and comorbidities. A physical examination will assess signs of fluid overload and pleural effusion findings.
Imaging studies will be utilized to confirm and grade the effusion. This includes a Chest X-ray (PA view) as an initial screening tool and Thoracic Ultrasound to assess effusion volume, echogenicity, and loculation. A CT Chest may be performed if ultrasound or X-ray findings are inconclusive, or if malignancy or complicated effusion is suspected.
A diagnostic thoracentesis will be performed under full aseptic conditions and ultrasound guidance to minimize complications. Approximately 30-60 mL of pleural fluid will be aspirated for diagnostic analysis, which includes gross appearance, total protein, LDH, glucose, pH, albumin, cell count, Gram stain, AFB smear, and cytology. Simultaneous serum laboratory tests will be collected at the same time as the thoracentesis for ratio calculations.
To evaluate diagnostic accuracy in the CKD population, four classification methods will be applied to each patient's samples:
241 studies on the registry are indexed under Pleural Effusion; 50 are open to participants now.
This study's planned enrollment of 100 is below the median of 140 across 93 observational studies indexed under Pleural Effusion.
Browse Pleural Effusion studies →Assiut University is the lead sponsor of 5,078 studies on the registry; 2,178 are open to participants now.
Of its 14 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
Counted across the registry records on this site, refreshed daily.
The study population comprises adult patients (≥18 years) with a confirmed diagnosis of Chronic Kidney Disease (CKD) Stages 3, 4, or 5 (eGFR \< 60 mL/min/1.73 m² for ≥3 months) who present with a radiologically confirmed pleural effusion. The cohort includes both pre-dialysis patients and those currently on maintenance hemodialysis or peritoneal dialysis. Participants will be enrolled from Assiut University Hospitals. Patients with acute kidney injury, trauma-related effusions, active malignancies, post-surgical effusions, or those who are pregnant are excluded from the sample.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adult patients (≥18 years old) with a confirmed diagnosis of Chronic Kidney Disease (CKD) Stages 3 through 5, including both pre-dialysis and dialysis-dependent patients, who present with a radiologically confirmed pleural effusion. Patients in this cohort will undergo an ultrasound-guided diagnostic thoracentesis alongside simultaneous serum laboratory testing. The collected pleural fluid and serum will be analyzed to classify the effusion (using Light's Criteria, abbreviated criteria, and SPAG) and to determine its underlying etiology.
Number of Participants Classified with Transudative or Exudative Pleural Effusions
The primary outcome assesses the number of participants whose pleural effusion is classified as either transudative or exudative. This classification is determined by applying Standard Light's Criteria to pleural fluid and simultaneous serum laboratory tests. An effusion is defined as exudative if any one of the following is met: pleural fluid/serum protein ratio \> 0.5 , pleural fluid/serum LDH ratio \> 0.6 , or pleural fluid LDH \> 2/3 of the upper normal limit of serum LDH. If none are met, it is classified as transudative.
Time frame: Baseline (at the time of diagnostic thoracentesis)
No study locations are listed for this record.
Start is estimated for May 2026; primary completion for May 2027, 12 months later.
Of 35 observational studies under Pleural Effusion, half reached primary completion within 26 months of starting (the median), counting those still running; a quarter within 15 and three quarters within 48. This study's planned 12 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
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