Pleural EffusionNCT07547852
Pleural Effusion Types in Chronic Kidney Disease
An observational study of Pleural Effusion and Chronic Kidney Disease, run by Assiut University.
Trial summary
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). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Pleural Effusion, Chronic Kidney Disease
- How many people
- 100 participants
- Where
- No sites listed yet
- Study dates
- May 2026to Jun 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Adult, Older adult
Study population: 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.
Who may be able to join
- Adults aged ≥18 years of either sex
- Confirmed diagnosis of CKD Stage 3-5 based on eGFR < 60 mL/min/1.73 m² for ≥3 months, as per KDIGO 2012 guidelines
- Radiologically confirmed pleural effusion on chest X-ray (CXR) or thoracic ultrasound
- Patients on hemodialysis or peritoneal dialysis, as well as those not yet on dialysis (CKD Stage 3-5 pre-dialysis)
- Willingness to provide written informed consent
Who cannot join
- Patients with Acute Kidney Injury (AKI) or acute-on-chronic kidney disease without prior CKD diagnosis
- Trauma-related pleural effusion (hemothorax, chylothorax)
- Known active malignancy with suspected malignant effusion
- Patients with post-surgical or iatrogenic pleural effusion
- Patients who refuse consent or are unable to undergo thoracentesis due to coagulopathy or other contraindications
- Pregnancy
About this study
Official title: Transudative and Exudative Pleural Effusion in CKD Patients
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.
Read more
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:
- Compare the chest fluid to the blood sample using standard criteria, abbreviated criteria, and the Serum-Pleural Effusion Albumin Gradient (SPAG).
- Determine the most common underlying causes of lung fluid across different stages of kidney disease.
- Identify which diagnostic formula is the most accurate for CKD patients, helping doctors avoid misdiagnosis and provide better, more targeted treatments.
Read the detailed description
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:
- Standard Light's Criteria: An effusion is exudative if the pleural fluid/serum protein ratio is >0.5, pleural fluid/serum LDH ratio is >0.6, or pleural fluid LDH is >2/3 of the upper normal limit of serum LDH.
- Abbreviated Light's Criteria: Uses only the protein (>0.5) or LDH (>0.6) ratios.
- Modified Light's Criteria: Requires at least two of the three original criteria to be positive.
- Serum-Pleural Effusion Albumin Gradient (SPAG): Calculated as Serum Albumin minus Pleural Fluid Albumin. A SPAG > 1.2 g/dL indicates a transudative effusion, while a SPAG ≤ 1.2 g/dL indicates an exudative effusion. SPAG is particularly valuable in CKD patients to prevent misclassifying a true transudate as an exudate.
- Conditions
- Pleural Effusion, Chronic Kidney Disease
- Keywords
- Light's Criteria, Serum-Pleural Effusion Albumin Gradient (SPAG), Transudate, Exudate, Thoracentesis, Uremic Pleuritis, Hemodialysis
- Medical subject headings
- Pleural Effusion, Renal Insufficiency, Chronic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| CKD Stage 3-5 with Pleural Effusion | 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. |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: Baseline (at the time of diagnostic thoracentesis)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Apr 2026
- Study startMay 2026 (estimated)
- Primary completionMay 2027 (estimated)
- Study completionJun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pleural EffusionStudies of the same condition, open and under way.
- More trials run by Assiut UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Assiut University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Abeer Hussien Mahmoud Abdelaziz, Assiut University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07547852
- Sponsor's protocol ID
- Pleural Effusion Types in CKD
- Status last verified
- Apr 2026
- First submitted
- 17 Apr 2026
- Last updated
- 23 Apr 2026
- Results posted
- No
Study at a glance
From the registry record, last updated by the sponsor on 23 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Transudative and Exudative Pleural Effusion in CKD Patients
- ClinicalTrials.gov ID
- NCT07547852
- Acronym / sponsor ID
- Pleural Effusion Types in CKD
- Conditions
- Pleural Effusion, Chronic Kidney Disease
- Keywords
- Light's Criteria, Serum-Pleural Effusion Albumin Gradient (SPAG), Transudate, Exudate, Thoracentesis, Uremic Pleuritis, Hemodialysis
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Assiut UniversityUniversity, hospital or other
- Study start
- May 2026 (estimated)
- Primary completion
- May 2027 (estimated)
- Study completion
- Jun 2027 (estimated)
- First posted
- 23 Apr 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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:
- Compare the chest fluid to the blood sample using standard criteria, abbreviated criteria, and the Serum-Pleural Effusion Albumin Gradient (SPAG).
- Determine the most common underlying causes of lung fluid across different stages of kidney disease.
- Identify which diagnostic formula is the most accurate for CKD patients, helping doctors avoid misdiagnosis and provide better, more targeted treatments.
Detailed description
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:
- Standard Light's Criteria: An effusion is exudative if the pleural fluid/serum protein ratio is >0.5, pleural fluid/serum LDH ratio is >0.6, or pleural fluid LDH is >2/3 of the upper normal limit of serum LDH.
- Abbreviated Light's Criteria: Uses only the protein (>0.5) or LDH (>0.6) ratios.
- Modified Light's Criteria: Requires at least two of the three original criteria to be positive.
- Serum-Pleural Effusion Albumin Gradient (SPAG): Calculated as Serum Albumin minus Pleural Fluid Albumin. A SPAG > 1.2 g/dL indicates a transudative effusion, while a SPAG ≤ 1.2 g/dL indicates an exudative effusion. SPAG is particularly valuable in CKD patients to prevent misclassifying a true transudate as an exudate.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| CKD Stage 3-5 with Pleural Effusion | – | –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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Age groups
- Adult, Older adult
- Study population
- 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.
Key inclusion criteria (5 listed)
- Adults aged ≥18 years of either sex
- Confirmed diagnosis of CKD Stage 3-5 based on eGFR < 60 mL/min/1.73 m² for ≥3 months, as per KDIGO 2012 guidelines
- Radiologically confirmed pleural effusion on chest X-ray (CXR) or thoracic ultrasound
- Patients on hemodialysis or peritoneal dialysis, as well as those not yet on dialysis (CKD Stage 3-5 pre-dialysis)
- Willingness to provide written informed consent
Key exclusion criteria (6 listed)
- Patients with Acute Kidney Injury (AKI) or acute-on-chronic kidney disease without prior CKD diagnosis
- Trauma-related pleural effusion (hemothorax, chylothorax)
- Known active malignancy with suspected malignant effusion
- Patients with post-surgical or iatrogenic pleural effusion
- Patients who refuse consent or are unable to undergo thoracentesis due to coagulopathy or other contraindications
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Number of Participants Classified with Transudative or Exudative Pleural Effusions
Time frame: Baseline (at the time of diagnostic thoracentesis)
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.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Apr 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
An observational study of Pleural Effusion and Chronic Kidney Disease, run by Assiut University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 23 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Participants Classified with Transudative or Exudative Pleural Effusions (time frame: Baseline (at the time of diagnostic thoracentesis)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Apr 2026.