From the Guidelines
Dialysis significantly affects urinalysis results in patients with glomerulonephritis by altering the levels of waste products, excess fluid, and proteins in the urine. This is because dialysis artificially filters blood urea nitrogen (BUN), creatinine, and electrolytes, leading to decreased concentrations of these substances in both blood and subsequently in any produced urine 1.
Key Considerations
- Protein levels in urine may appear lower after dialysis as some proteins are removed during the procedure, potentially masking the proteinuria characteristic of glomerulonephritis.
- The timing of urinalysis relative to dialysis sessions is crucial; samples collected immediately after dialysis may show falsely reduced levels of protein, casts, and cellular elements compared to pre-dialysis samples.
- Dialysis can affect urine volume and concentration, with many patients on regular dialysis producing minimal urine (oliguria) or no urine (anuria) as their kidney function declines.
Clinical Implications
- For accurate assessment of glomerulonephritis activity, clinicians should ideally collect urinalysis samples before dialysis sessions and interpret results in context of the patient's dialysis schedule, residual kidney function, and overall clinical picture.
- Understanding these effects helps prevent misinterpretation of disease activity or treatment response in glomerulonephritis patients undergoing dialysis, as preserving residual kidney function (RKF) is a major objective in the management of dialysis patients 1.
Preservation of Residual Kidney Function
- Interventions that slow the decrease in kidney function in patients with chronic kidney disease (CKD) may also slow the decrease in RKF in patients on dialysis therapy.
- Agents or events that are nephrotoxic in general can be assumed to be nephrotoxic to RKF, and preference should be given to the use of ACE inhibitors or ARBs in patients with RKF who need antihypertensive medication 1.
From the Research
Effect of Dialysis on Urinalysis Results in Patients with Glomerulonephritis
- The provided studies do not directly address how dialysis affects urinalysis results in patients with glomerulonephritis. However, they offer insights into the relationship between kidney function, proteinuria, and the progression of chronic kidney disease (CKD) 2, 3, 4, 5, 6.
- Glomerulonephritis is characterized by the presence of urinary abnormalities, including proteinuria and hematuria. The disease can lead to chronic kidney disease and end-stage renal disease, requiring dialysis or kidney transplantation 2.
- Proteinuria is a strong marker for the progression of CKD and is associated with increased cardiovascular morbidity and mortality 3. The presence of albuminuria or proteinuria indicates kidney damage and is used, along with the estimation of glomerular filtration rate, to evaluate CKD.
- Studies have shown that treatment with angiotensin-converting enzyme inhibitors (ACEi) or angiotensin II receptor blockers (ARBs) can reduce proteinuria and slow the progression of CKD in patients with primary renal diseases 4, 5.
- High levels of uric acid (UA) have been associated with an increased risk of earlier start of dialysis in incident pre-dialysis patients, although they do not appear to accelerate the decline in renal function 6.
- The relationship between dialysis and urinalysis results in patients with glomerulonephritis is complex and likely influenced by various factors, including the underlying disease process, the presence of proteinuria, and the use of medications such as ACEi or ARBs 2, 3, 4, 5, 6.
Key Findings
- Proteinuria is a key feature of glomerulonephritis and a strong marker for CKD progression 2, 3.
- ACEi and ARB treatment can reduce proteinuria and slow CKD progression 4, 5.
- High UA levels are associated with an earlier start of dialysis in pre-dialysis patients 6.
- The provided studies do not directly address the effect of dialysis on urinalysis results in patients with glomerulonephritis, highlighting the need for further research in this area 2, 3, 4, 5, 6.