The Kidneys have three main functions; excretion of waste, maintenance of extracellular fluid and hormone synthesis.
Acute renal failure is diagnosed when renal excretory function declines rapidly over hours or days and is potentially reversible. It is usually recognised after biochemical testing reveals increased blood levels of urea and creatinine. There are many causes including medical, surgical, traumatic, obstructive and obstetric.
Chronic renal failure (CRF) is diagnosed when renal excretory function declines over months to years and is irreversible; the most common cause of chronic renal failure is diabetes mellitus. Chronic renal failure can be classified as either moderate or end stage. The prevalence of moderate chronic renal failure (creatinine 200-500umol/L) is about three times greater than end-stage renal failure (ESRF). Patients with end stage renal failure (creatinine >500umol/L) require either long-term renal replacement treatment (haemodialysis) or renal transplant in order to survive.
Haemodialysis remains the default therapy for all end stage renal failure patients. Despite the success of transplantation and peritoneal dialysis, haemodialysis continues to have the highest rate of growth of all treatment modalities
Diagnosis of both acute and chronic renal failure is usually based on results from a plasma/serum renal profile. The renal profile commonly consists of the following tests: urea, creatinine, sodium, potassium, chloride, bicarbonate, phosphate and uric acid. Once renal failure has been diagnosed these parameters should be tested on a regular basis. Dialysis fluid is often tested to ensure the dialysis process in efficient.
The following are the Renal Association standards for end stage renal failure:
in pre-dialysis patients serum potassium levels should be between 3.5 and 6.5mmol/L. In peritoneal dialysis patients levels should be between 3.5 and 5.5mmol/L.
in pre-dialysis patients serum bicarbonate levels should be between 20 and 26mmol/L if measured with minimal delay after venepuncture. In peritoneal dialysis patients levels should be between 25 and 29mmol/L if measured with minimal delay after venepuncture.
In pre-dialysis patients serum phosphate levels should be below 1.8mmol/L.
In pre-dialysis patients serum calcium levels (adjusted for albumin) should be between 2.2 and 2.6mmol/L.
Serum albumin should be measured regularly a concentration below 35g/L, using a Bromocresol Green assay, or below 30g/L using a Bromocresol Purple assay, should prompt clinical reassessment of the patient.
Haemoglobin levels in chronic renal failure patients should be above 10g/dL within 6 months of being examined by a nephrologist unless there is a specific reason.
Normal levels are between 2 and 7.5 mg/dL, elevated levels are associated with renal disease and failure.
Renal transplantation remains the most successful, economical and hence cost effective treatment for patients with end state renal failure. Various immunosuppressive regimens involving mono, double or triple therapy using Prednisolone, Azathioprine, Cyclosporin microemulsion (Neoral TM), Tacrolimus, Mycophenolate mofetil or Rapamycin are employed with appropriate therapeutic drug monitoring.
Other common diseases affecting the kidney include the formation of renal stones and nephropathy/proteinuria. In addition to a renal profile, serum or plasma levels of calcium uric acid and urinary levels of calcium, phosphate, sodium, potassium, bicarbonate, magnesium, creatinine, urate, oxalate, citrate, cystine, pH and creatinine clearance may be of interest in the investigation of renal stones.
Randox provide test kits for the complete renal profile please contact us for more information.