The most probable answer to question 5 = d Comments about answers to question 5:
a. Since a urine specific gravity of 1.010 may represent a normal or abnormal value, further information must be obtained before
renal concentrating and diluting capacity can be assessed. However, this specific-gravity value should arouse suspicion that
an underlying disorder may be present.
b. See preceding comments for a.
c. See preceding comments for a.
d. See preceding comments for a.
e. See preceding comments for a.
The most logical answer to question 6 = c Comments about answers to question 6.
a. Concentration of urine to this degree indicates that an adequate population of nephrons are functional to prevent primary
renal failure. The small quantity of protein and high specific gravity indicate that primary renal failure and primary glomerular
disease are improbable.
b. See comments in a. There is no evidence of renal failure: Magnitude of urine concentration indicates that renal failure is
improbable. However, observation of many casts indicates that the renal disease is active and could progress to renal failure.
c. Detection of many granular casts is indicative of renal disease affecting at least the renal tubules, even though urine concentration
indicates that the disease is not of sufficient magnitude to cause renal failure. The large number of casts suggests (but
does not prove) that the disorder is acute. The acute renal disease is associated with an inflammatory response.
d. This answer is possible, although c is more probable. Additional information would be required to prove or disprove either
The findings are definitely abnormal.
The most probable answer to question 7 = a Comments about answers to question 7:
a. Detection of mild proteinuria and occasional struvite crystals in highly concentrated urine is a common finding in dogs.
b. This interpretation is a possibility, but not a probability. Additional follow-up studies would be required to prove glomerular
c. This interpretation is a possibility, but very unlikely in light of other findings.
d. Damage to the mucosa lining the urinary tract would be expected to be associated with an inflammatory response, hematuria
and/or many transitional epithelial cells.
e. Further information would be required to verify this conclusion.
The most probable answer to question 8 = b Comments about question 8
a. The conclusion could not be established without knowledge of the patient's hydration status, a water-deprivation test and
perhaps a vasopressin-response test. The fact that urine dilution of this magnitude has occurred suggests, but does not prove,
that a sufficient population of functional nephrons is present to concentrate urine.
b. Dilution of glomerular filtrate to this degree requires a sufficient population of functional nephrons (at least one-third
in dogs) to remove solute in excess of water (e.g. urine dilution).
c. See comment a.
d. It is not possible to evaluate the functional status of all nephrons on the basis of urine specific gravity. Many nephrons
may be nonfunctional (up to two-thirds in dogs, and probably more in cats) without loss of the ability to concentrate urine,
at least to some degree.
See comment b.