Chapter 4: Physical Examination

CHAPTER 4: PHYSICAL EXAMINATION ABNORMAL URINE COLOR OF URINE Dark Yellow/Amber/Orange - The physical examination of urine includes the determination of can be caused by the presence of abnormal pigment of bilirubin. - If bilirubin is present, it will be ● Urine Color detected ● Clarity examination. ● Specific Gravity - during chemical its presence is suspected if yellow foam appears when the specimen is Color - the color of urine varies from almost colorless to black shaken. - a large amount of white foam Normal Urine Color - common descriptions indicated an increased concentration include pale yellow, ellow, and dark yellow. of protein. Urochrome - the yellow color of urine is - photo-oxidation of large amounts of caused by the presence of a pigment, which excreted urobilinogen to urobilin also Thudichum named in 1864. produces a yellow-orange urine; yellow foam does not appear when shaken. - photo-oxidation of bilirubin imparts a yellow-green color to the urine caused by the presence of biliverdin. - Frequently urinalysis encountered lab specimen is caused in the yellow-orange by the administration of phenazopyridine or azo-gantrisin compounds to people TWO ADDITIONAL PIGMENTS: Uroerythrin - a pink pigment, is most evident in specimens that have been who have urinary tract infection. Red/Pink/Brown - abnormal urine color is the presence refrigerated, resulting in the precipitation of amorphous urates. Urobilin - an oxidation product of normal urinary constituent urobilinogen, imparts an orange-brown color to urine that is not fresh. One of the most common causes of of the blood. - red is the usual color that blood produced in urine but the color may range from pink to brown, depending on the amount of blood, the pH of - the urine, and the length of contact. - RBCs remaining in an acidic urine - of skeletal muscle produces myoglobin. - myoglobin is more rapidly cleared for several hours produce a brown from the plasma than is hemoglobin urine and, therefore, does not affect the due to the oxidation of hemoglobin to methemoglobin. - breakdown color of the plasma. Fresh brown urine containing blood - fresh urine containing myoglobin also indicates glomerular bleeding. frequently hemoglobin and myoglobin produce reddish-brown red urine and result in positive containing hemoglobin. chemical results for blood. exhibits color a more than urine Port wine - urine specimens containing porphyrins also may appear red, resulting from the oxidation of porphobilinogen to porphyrins. - they are often referred to as having the color of port wine. Non Pathogenic causes of red urine include: ● When RBCs are present, the urine is red and cloudy. ● if hemoglobin 2. ingestion of highly pigmented foods or myoglobin is present, the specimen is red and clear. ● distinguishing 1. Menstrual contamination 3. medications Brown/Black - between and have negative chemical test patient’s plasma. results for blood, inasmuch as they Hemoglobinuria - may resulting in vivo breakdown of RBCs The possibility of hemoglobinuria being produced from the in vitro lysis of RBCs also must be considered. Myoglobinuria is that turn brown or black on standing may be possible by examining the is accompanied by red plasma. specimen recommended for urine specimens hemoglobinuria and myoglobinuria - additional contain melanin or homogentisic acid. Melanin - is an oxidation product of the colorless pigment, melanogen, produced in excess when malignant melanoma is present. Homogentisic acid - a examining the mixed specimen while metabolite of phenylalanine, holding it in from of a light source imparts a black color to alkaline urine from persons with the inborn-error of metabolism called alkaptonuria. Blue/Green - Pathogenic causes of blue/green are limited to bacterial infections, including urinary tract infection by Pseudomonas species and intestinal tract infections resulting in increased urinary indican. - Ingestion of breath observation of specimen collection bags from frequently - hospitalized reveals freshly voided normal urine is usually clear, particularly if it is a deodorizers (Clorets) can result in a green urine. - Normal Clarity midstream clean-catch specimen. - precipitation of amorphous phosphates and carbonates may patients cause a white cloudiness. abnormally colored urine. - phenol derivatives found in certain intravenous medications produce green urine on oxidation. - a purple staining may occur in catheter bags and is caused by indican in the urine or a bacterial infection. Frequently caused by Klebsiella or Providencia spp. CLARITY - It is a general term that refers to the transparency or turbidity of a urine specimen. - in routine analysis, clarity is a determined in the same manner that ancient physicians used: by visually Nonpathologic Turbidity - the presence of squamous epithelial cells and mucus, particularly in specimens from women, can result in a hazy but normal urine. - specimens that are allowed to stand or are refrigerated also may develop turbidity that is nonpathologic. - refrigerated specimens frequently develop a thick turbidity caused by the precipitation of amorphous phosphates, carbonates, and urates. Amorphous phosphates and carbonates - Specific Gravity - the glomerular filtrate by selectively produce a white precipitate in urine reabsorbing essentia chemicals and with an alkaline pH water from glomerular filtrate is one Amorphous urates - The kidney’s ability to concentrate of produce a precipitate in acidic urine that resembles brick dust due to the presence of uroerythrin. the kidney’s most important functions. - Specific gravity additional function, determine provides which whether an is to specimen concentration is adequate to ensure the accuracy of chemical test - The specific gravity of the plasma filtrate entering the glomerulus is 1.010. - density of a solution compared with Pathologic Turbidity - the most commonly encountered the density of a similar volume of pathologic causes of turbidity in a distilled water (SG 1.000) at a similar fresh specimen are RBCs, white temperature. Isosthenuric blood cells (WBCs) - Specific gravity is defined as the clear urine is not always normal. However, with the tests, most abnormalities in clear urine will be detected prior to the used to describe with a specific gravity of 1.010. increased sensitivity of the routine chemical microscopic analysis. - Hyposthenuric - specimens below 1.010 Hypersthenuric - above 1.010 Normal Random Specimen - it may range from approximately 1.002 to 1.035, depending on the patient’s amount of hydration. - Specimens measuring lower than 1.002 probably are not urine. - Most random specimens fall between 1.015 and 1.030. Refractometer - Refractometry determines the concentration of dissolved particles in a specimen by measuring refractive index. - The refractometer provides the distinct advantage of determining specific gravity using a small volume of specimen (one or two drops) - Temperature. is compensated between 15C and 38C Refractive Index - A refractive index is a comparison of the velocity of light in air with the velocity of light in a solution. Odor - Although it is seldom of clinical significance and is not part of the routine urinalysis, urine odor is a noticeable physical property. - Ingestion of certain foods, including onions, garlic, and asparagus, can cause unusual or pungent urine odor.