Chapter 4 Urine tests and renal function tests

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Chapter 4 Urine tests and renal
function tests
Samples collection and sending A first morning
voided urine specimen obtained by a clean catch
technique yields the most information. Other
collections of urine might have their specific
usage ( random urine, postcibal urine, 12 hours
urine, 24 hours urine, etc.) The urine should be
examined promptly by both chemical and
microscopic means.
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Contents and clinical significance of URT

• General property
• Urine volume Normal volume of urine in 24 hours
  should be 1000 -2000 ml .
• Polyuria gt 2500ml/ 24 hrs chronic nephritis ,
  diabetes insipdus, diabetes mellitus
• Oliguria lt 400 ml/ 24 hrs acute nephritis
  ,sereve shock, urinary tract obstruction
• Anuria lt 100 ml/ 24 hrs acute renal failure

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Color

• Hematuria microscopic hematuria is defined as
  more than 3 RBCs/HP on a centrifuged urine
  specimen. Naked-eye hematuria is defined as more
  than 1 ml blood in one liter urine.
• Hemoglobinuria the color looks like strong tea
  or wine because of the existing of free
  hemoglobin
• Pyuria or becteriuria presence of more than 5
  WBCs /HP or germs with cloudy-looking
• Bilirubinuria presence of direct bilirubin
  with dark-yellow color
• Crystoluria presence of salts crystal with
  cloudy-looking

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• PH 6.5
• aciduria acid acidosis
• alkaluria alkalosis , renal tubular acidosis
• Specific gravity 1.015-1.025
• lower SG chronic renal failure, diabetes
  insipdus
• high SG acute nephritis, diabetes mellitus,
  heart failure

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• Chemical tests include detection the presence
  of protein, occult blood, glucose and ketone in
  the urine.
• Urine protein normal (-) or 20-80 mg/24
  hrs,
• abnormal ( ) or gt 150 mg / 24 hrs
• Urine glucose normal (-) or 0.56-
  5.6mmol/L, diabetic urine ( glucosuria) (-)
• Urine ketone normal (-),ketonuria
  (-)

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• Microscopic examination ( urine sediment
  tests)
• Cells In normal urine, RBC and WBC are rare (
  RBC 0-1 / HP , WBC lt 5 / HP ) . Epithelial
  cells ( oval fat bodies ) are commonly found
  in urinary sediment and may derive from any site
  along the urinary tract from the renal pelvis to
  the urethra. When renal tubular epithedlial cells
  or renal cells appears in the urine, it is
  pathological change.

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• Casts
• cellular casts (erythrocyte casts, leukocyte
  casts, renal tubular cell casts )
• granular casts( coarse and fine granule)
• hyaline casts
• waxy casts
• renal failure casts
• Crystal bodies
• Pathogen

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Microscopic examination of the urine
finding associations
casts red blood cell
glomerulonephritis, vasculitis white blood
cell interstitial nephritis,
pyelonephritis epithelial cell
acute tubular necrosis,interstitial
nephritis,
glomerulonephritis granular
renal parenchymal disease (non-specific)
waxy ,broad advanced renal
failure hyaline
normal finding in concentrated urine fatty
heavy proteinuria
cells red blood cell
urinary tract infection or inflammation
white blood cell urinary tract infection
or inflammation
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Renal function tests
Tests of glomerular function

• Endogenous creatinine clearance rate (Ccr)
  Determination of the clearance of endogenous
  creatinine is a more convenient test and provides
  a reasonable estimate of the GFR.
• The creatinine clearance is calculated as Ccr
  (ml/min)Ucr(mg/dl)xV(volume of urine in 24
  hours, ml/min) / Pcr (mg/dl). Normal range is
  80-120 ml/min/1.73m2.

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• Blood concentration of creatinine (Cr) and urea
  nitrogen (BUN) Creatinine is a metabolite of
  creatine, a major muscle constituent. In a given
  individual, the daily rate of production of
  creatinine is constant and is determined by the
  mass of skeletal muscle. Urea is the major
  product of protein metabolism, and its productoin
  reflects the dietary intake protein as well as
  the protein catabolic rate. BUN is often used in
  conjunction with the Cr as a measure of renal
  function.
• Cr 53-106 umol/L (M), 44-97 umol/L (F)
• BUN 3.2-7.1 mmol/ L (adult) , 1.8-6.5 mmol/ L
  (children)

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Tests of renal tubule function
Renal tubular function is evaluated by tests
that examine the ability of the kidney to
maintain salt and water balance as well as
acid-base balance.

• Urine specific gravity (3 hours urine) test
• Day uine (2/3-3/4) should be more than night
  urine (1/3-1/4), hightest SG gt 1.025 ,lowest SG lt
  1.003
• Phenolsulfonphthalein excretion test (PSP)
• excretion rate 15 min gt 25, 2 hrs (total) gt
  55
• Carbon dioxide combining power ( CO2CP)normal
  22-31 mmol / L, elevated CO2CP metabolic
  acidosis, respiratory alkalosis, declined CO2CP
  respiratory acidosis, metabolic alkalosis

a.
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• Automatic urine analyzer (10 items)
• GLU(-), BIL(-), UBG(3.2umol/L),
• NIT(-), KET(-), PRO(-), PH(6.5),
• BLD(-), LEU(-), SG(1.025)

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Case analysis
History and physical examination A 48-year- old
female patient was admitted with the complains of
severe headache with a fever, edema in her face
and eyelids for 3 days. From yesterday, she found
her amount of urine was decrease once a day . The
color of her urine is reddish and cloudy.
Physical examination her blood pressure is
180/100 mm Hg , there is severe pitting edema in
her face and legs.
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Question

• After physical examination, what laboratory
  test do you plan to do?
• How do you think or judge this case?
• What urinary abnormalities and renal function
  test results do you probably find?
• Teacher give laboratory results of this case
  and discuss the case .