Urinalysis - The Carter Center

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Specimen Urine containing hemoglobin appears brown or brown-gray on color and is usually cloudy. It should be tested as soon as possible after it has been passed. Laboratory Tests for Hemoglobin Numerous Tests are available for the detection of hemoglobin in urine. The tests commonly used are: - Guaiac - Benzidine - Occultest - Reagent Strip Tests (Hemastix) Benzidine is no longer used, as it is a carcinogen. General Principle of the Tests These tests are based on the same general principles and reaction. They all involve the presence of peroxidase activity of the hemoglobin and hydrogen peroxide (H 2 O 2 ) or a suitable precursor which librates oxygen. Peroxidase of the hemoglobin molecule liberates oxygen from hydrogen peroxide and the librated oxygen reacts with an organic reagent or chromogen (gum guaiac or 0-tolidine) to give a colored compound, which is usually blue or green. The intensity of the color depends on the amount of librated oxygen. The amount of librated oxygen depends on the peroxidase ctivity of hemoglobin molecule, which intern depends on the amount of hemoglobin found in the urine. These reactions are summarized below: 75 Hemoglobin + H 2 O 2 Perosidase Oxygen Oxygen + Chromogen Blue or green oxidation products
Since all these tests are based on the peroxidase activity of hemoglobin, other substances with peroxidase activity also give positive reactions in the tests. Factors that Affect Hemoglobin Determination False negative - High specific gravity such as heavy proteinuria (over 5 g/1). This prevent lysis of RBCs and may reduce the color reaction. - Low to false negative results are obtained if the urine contains large amounts of ascorbic acid. - Nitrite delays test reaction. - Formaline used as preservative, fix the cell and prevent hemolysis. False positive - Low specific gravity < 1.010 enhances lysis and produces color reaction. - Microbial peroxidase produces false the color reaction. - False positive reactions can result from the presence of contaminating oxidizing detergents on the urine such as bleach. A. Guaiac Test Procedure: 1. Pour into a test tube 4 drops of urine and a few drops of concentrated acetic acid. 2. Pour the following into a second test tube - A knife point of Guaiac - 2 ml ethanol (95%) - 2 ml fresh 3% H 2 O 2 Mix the above slowly and pour the same into the side of the urine tube. 76
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LECTURE NOTES For Medical Laborator
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Preface i Books on Medical history
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Contents iii Preface Aknowledgement
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v List of Table Table 1 Methods of
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Abbreviations vii ADH : Antidiureti
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ix This lecture note is prepared fo
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Components of the renal system are
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4 collecting tubule. A number of th
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- Electrolytes - Cast parasites and
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Exercise 1. 8 Answer the Following
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10 plastic tube with a plastic snap
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12 24- Hour specimen - a specimen o
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• Distruction of glucose by bacte
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16 2.3 Type of Examination in Routi
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18 CHAPTER THREE Physical Examinati
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• Myxedema • Some type of tubul
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metabolic conditions, the color and
Page 35 and 36: - By letting it to stand for more t
Page 37 and 38: • Degree of cloudiness of the uri
Page 39 and 40: - Look for color change of red litm
Page 41 and 42: tubules of the nephron, depending o
Page 43 and 44: Specimen: It should be the first ur
Page 45 and 46: gravity is elevated because of the
Page 47 and 48: 36 Exercises Say True or False 1. U
Page 49 and 50: 38 constituents of urine. 4.1 Deter
Page 51 and 52: 40 Causes of Glycosuria • Physiol
Page 53 and 54: specimen and the results are graded
Page 55 and 56: unnecessary.The reaction for clinit
Page 57 and 58: 46 The overall reaction is : Glucos
Page 59 and 60: 2. Dip part of the tape into the ur
Page 61 and 62: metabolism or absorption, the body
Page 63 and 64: 4. If acetone or acetoacetate is pr
Page 65 and 66: immediately. For this reason, Gerha
Page 67 and 68: contains only traces of protein, in
Page 69 and 70: It requires large volumes ( 0.5 to
Page 71 and 72: due to urates, uric acid urea and b
Page 73 and 74: 62 Preparation of Acetic Acid Reage
Page 75 and 76: urine contains more than 100mg/dl p
Page 77 and 78: cell disease (hepatocellular diseas
Page 79 and 80: 68 1. Icotest Tablet Test The Ictot
Page 81 and 82: characteristic color with the other
Page 83 and 84: 72 Sensitivity Urobilistix detects
Page 85: Hemoglobinuria may occur with sever
Page 89 and 90: peroxidase activity) catalyzes the
Page 91 and 92: 80 4.9 Determination of Nitrite Int
Page 93 and 94: The pink color is therefore related
Page 95 and 96: - Pancreatic insufficiency. - Intes
Page 97 and 98: 86 A. Ferric Chloride Test Principl
Page 99 and 100: 88 CHAPTER FIVE Microscopic Examina
Page 101 and 102: • If it is difficult to deliver w
Page 103 and 104: 92 5.3 Urinary Sediments Classifica
Page 105 and 106: Red blood cells are some what round
Page 107 and 108: EPITHELIAL CELLS • Normally few e
Page 109 and 110: 98 CASTS • Formed by precipitatio
Page 111 and 112: 100 c. Waxy Casts (Renal Failure Ca
Page 113 and 114: 102 • Always the condenser should
Page 115 and 116: 104 • Large, measuring 275-399 x
Page 117 and 118: 106 Report of the Result The bacter
Page 119 and 120: 108 Some drug crystals in the urine
Page 121 and 122: 110 - Have various tiny squarish, b
Page 123 and 124: 112 - Size is about 20 μm. - Often
Page 125 and 126: 114 They can be confirmed by logos
Page 127 and 128: 116 Nucleus Cytoplasm Squameous epi
Page 129 and 130: 118 Reagent No.5 Bleach for Preserv
Page 131 and 132: 120 Reagent No.16 Saturated Sodium
Page 133 and 134: 122 III. Table 4: Correct and Incor
Page 135 and 136: 124 Glomeurlar Filtration Rate: The
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126 Urinometer: A small glass instr
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Urinalysis - The Carter Center

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