The renal function test (RFT) is a group of assessments used to evaluate kidney functionality, diagnose renal impairment, and monitor treatment effectiveness. It includes tests for glomerular and tubular function, focusing on parameters such as serum urea, creatinine, and electrolytes, with specific reference ranges provided. Abnormal values of these parameters can indicate various conditions, including dehydration, renal failure, and electrolyte imbalances.

1. Renal Function Test
RFT
By:
Fatima Ali

2. Renal function test(RFT), also
called Kidney function test is a
group of tests used to assess the
functions of kidney
What is RFT ?

3.  To assess functional capacity of kidneys
 To diagnose renal impairment
 To assess the severity and progression of renal
impairment
 To assess the effectiveness of treatment
Why Renal Function Tests needed?

4. Can be divided into two categories:
 Test for glomerular function
 Serum Urea
 Serum Creatinine
 Clearance tests
 Tests for tubular function
 Urine concentration test
 Dilution test
 Para amino hippuric acid clearance test
 Acidification test
 Urine examination: Important for assessing both glomerular
and tubular function
Renal function test

5. The following parameters are commonly included in
assessing glomerular function
 Serum Urea ( 10-45 mg/dl)
 Serum Creatinine (0.6 –1.2 mg/dl)
 Serum Uric acid (males 3.5-7.2 mg/dl, females 2.6-6 mg/dl)
 Total protein (6.0-8.0 g/dl)
 Serum albumin (3.0-5.0 g/dl)
Serum electrolytes
 Na (135-150 mEq/L)
 K (3.5-5.0 mEq/L)
 Phosphate (2.8-4 mg/dl)
 Calcium (8.0-10.2 mg/dl)
Test for glomerular function

8. Measurement of urea is used to:
 evaluate renal function
 to assess hydration status
 to determine nitrogen balance
 to aid in the diagnosis of renal disease
 and to verify adequacy of dialysis.
Serum Urea

9. Azotemia:
elevated conc. of urea in blood.
Uremia:
very high plasma urea concentration accompanied by
renal failure. Causes of blood urea elevations are: Pre-
renal Renal and post-renal
Disease Correlations

10.  Anything that produces a decrease in functional blood
volume, include: Congestive heart failure, Shock,
Hemorrhage, Dehydration High protein diet or
increased catabolism (Fever, major illness, stress)
Pre-Renal Azotemia:

11. Decreased renal function causes increased blood urea due
to poor excretion Acute & Chronic renal failure
Glomerulonephritis Tubular necrosis & other Intrinsic
renal disease
Renal Azotemia:

12. Post-Renal Azotemia
Obstruction of urine flow Renal calculi Tumors of
bladder or prostate Severe infections

13. Decreased blood urea
Low protein dietary intake Liver disease (lack of
synthesis) Severe vomiting and/or diarrhea(loss)

14.  Creatinine is the waste product of creatine phosphate,
a compound found in the skeletal muscle tissue.
 It is excreted entirely by the kidneys.
 The creatinine level is affected primarily by renal
dysfunction and is thus very useful in evaluating renal
function.
 Increased levels of creatinine indicate a slowing of the
glomerular filtration rate.
 Female: 0.6–1.2 mg/dL
 Male: 0.8–1.4 mg/dL
Serum Creatinine

15. Possible Meanings of Abnormal Values:
 Congestive heart failure
 Glomerulonephritis
 Nephritis
 Pyelonephritis
 Renal failure
 Urinary obstruction
 Dehydration

16. it is filtered by the glomerulus and secreted by the distal
tubules into the urine, in which most uric acid is
reabsorbed in the proximal tubules and reused.
Serum Uric Acid

17. Possible Meanings of Abnormal Values:
Increased (hyperuricemia):
Congestive heart failure
Glomerulonephritis
Alcoholism
Gout
Dehydration
Trauma and surgery.
Administration of certain drugs (diuretics, cyclosporine,
etc.)

18. Decreased (hypouricemia)
Liver disease
Renal tubular defects
Defectivetubular reabsorption(Fanconi syndrome)
Chemotherapy with azathioprine or 6mercaptopurine
Overtreatment with allopurinol

19.  Sodium is decreased (hyponatremia) and potassium is
increased (hyperkalemia) in chronic kidney disease
(CKD) as kidney reabsorb sodium in exchange of
potassium
 Chloride and phosphate is increased in CKD
 Calcium is decreased as vitamin D is deficient
Serum electrolytes

20. 1. Hypernatremia :
Its defined as an increased sodium concentration in
plasma water, and is generally diagnosed at serum
sodium levels >145 mmol/L.
Hypernatremia is always associated with an increased
effective plasma osmolality, and hence with a reduced
cell volume.
Sodium disorders:

21. 2. Hyponatremia:
Is defined as reduced plasma sodium concentration to a
value less than 135 mmol/L.
The five most common causes of Hyponatremia are
overhydration, diuretics, SIADH, diabetic
hyperosmolarity and Addison’s disease.
Sodium disorders

22. 1. Hypokalemia:
 Is a plasma K concentration below the lower limit of
the reference range.
 Hypokalemia can occur with GI or urinary loss of K or
with increased cellular uptake of K.
Potassium disorders:

23.  Hyperkalemia may be caused by one of three
mechanisms:
 (1) shift of potassium from the cells to the ECF
 (2) increased potassium intake
 (3) reduced renal potassium excretion.
Hyperkalemia:

24. Any question?
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25. Thank you