Kidney function tests

KIDNEY FUNCTION TEST
  • 30 cm needles punch such as Franklin silvermann needle is introduced into each kidney under visual control by laprotomy/Endoscopy or into left kidney under manual guidance through the wall of the rectum. Perirenal hematomas or transient hematuria are the complications.

Volhard’s concentration test:

  • Based on specific gravity of urine. An animal on dry ration is deprived of water for 12 hours. Urine samples collected from the beginning and end of the period. In healthy cattle, specific gravity reaches 1.030 or while in cattle with little kidney function, the specific gravity is below 1.020.

Dye test:

  • An I/V injection of indigo carmine, the urine is stained with dye and normally passed within 4-8 minutes. Methylene blue injection I/M, 0.4 ml of 2% solution per kg body weight normally reaches its maximum excretion after 1 hour and complete excretion within 24 hours. Kidney disease delays dye excretion. The result of dye test can be improved by measuring blood clearance instead of excretion time.
  • The half life of I/V administered phenol red (80-100 ml) of 0.06% solution is normally excreted within 20.6 minutes while in cattle with kidney diseases it exceeds more than 1 hour.

Water deprivation test:

  • When patients are deprived of fluid for suitable period of time approximately 24 hours, endogenous ADH is released from pituitary gland as a compensatory mechanism.

Interpretation:

  • If specific gravity is less than 1.025, the following conclusions may apply
  • Impaired ability of the kidney to concentrate urine.
  • Impairment in the production or release of ADH

Exogenous ADB (pitressin test):

  • By injecting exogenous ADH, the permeability of normal distal tubules and collecting ducts of water is increased.

Repositol vasopressin test:

  • Inject I/M 3-5 units vasopressin tannate in oil.
  • Withhold food and fluids.
  • Empty the bladder 3 hours after injection.
  • Collect urine samples at 3rd, 6th, 9th hours after administration of ADH.

Sodium sulfanilate test:

  • 10mg/kg body weight as a 20% solution in water is injected I/V and measured at 10, 15, 30, 60, 90 minutes after injection shows the t ½ value of 39.5 + 40.4 minutes.

Scintigraphic imaging:

  • Used for estimation of GFR, renal plasma flow, and plasma rennin activity by scintiagraphic imaging using 99m to glucoheptonate.
Last modified: Thursday, 19 April 2012, 10:01 AM