1 URINALYSIS AND BODY FLUIDS (SEROUS FLUIDS) Dr. Essam H. Jiffri

2 SEROUS FLUIDS - The closed cavities of the body mammal; the pleural, pericardial, and peritoneal cavities are each liner by two membranes referred to as the serous membranes.

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4 SEROUS FLUIDS -One membrane lines the cavity wall (parietal membrane), and the other covers the organs within the cavity (visceral membrane). -The fluid between the membranes which provides lubrication as the surfaces move against each other, is called serous fluid.

5 SEROUS FLUIDS - Normally only a small amount of serous fluid is present because production and absorption take place at a constant rate.

6 Formation - Serous fluids are formed as ultrafiltrates of plasma, with no additional material contributed by the membrane cells. - Production and reabsorption are subject to hydrostatic and colloidal (oncotic) pressures from the capillaries serving the cavities under normal conditions.

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8 Formation - The greater hydrostatic pressure in the systemic capillaries on the parietal side favors fluid production through the parietal membrane and reabsorption through the visceral membrane.

9 Formation - Fluids for laboratory examination are collected by needle aspiration from the respective cavities. -These aspiration procedures are referred to as:  thoracentesis (pleural)  pericardiocentesis(pericardial).  paracentesis (peritoneal).

10 Formation - Abundant fluid is usually collected; therefore, suitable specimens are available for each section of the laboratory. - An anti-coagulated specimen is needed for cell counts, a sterile tube for culture. - Large volumes of fluid should be prepared prior to microbiologic and cytologic examinations

11 General Laboratory Procedures - Routine fluid examination including classification as a transudate or exudate, appearance, cell count, differential, chemistry and microbiology procedures is performed in the same manner on all serous fluids.

12 General Laboratory Procedures - Cell counts are usually performed manually using the Neubauer counting chamber. - Differential counts are performed on (Wright­ stained smears). - Any suspicious cells been on the differential should be referrer to the cytology laboratory or the pathologist.

13 Summary of Serous Fluid Testing Pleural Fluid Normal appearance: Clear, pale yellow Turbidity: White blood cells and microorganisms Blood: Traumatic injury, malignancy, traumatic tap Milky: Chylous or pseudochylous material Neutrophils: Bacterial infection Lymphocytes: Tuberculosis, malignancy Normal glucose: Parallels serum glucose Low glucose: Tuberculosis, rheumatoid- inflammation, malignancy Low pH: Tuberculosis, malignancy, esophageal rupture Elevated amylase: Pancreatitis

14 Summary of Serous Fluid Testing Pericardial Fluid Normal appearance: Clear, pale yellow Milky: Lymphatic drainage Turbidity: Infection, malignancy Blood: Tuberculosis, tumor, cardiac puncture Neutrophils: Bacterial endocarditis Low glucose: Bacterial infection, malignancy

15 Summary of Serous Fluid Testing Peritoneal Fluid Normal appearance: Clear, pale yellow Turbidity: Peritonitis, cirrhosis Blood: Trauma Neutrophils: Peritonitis Low glucose: Tubercular peritonitis, malignancy Elevated amylase: Pancreatitis, gastrointestinal perforation Elevated alkaline phosphatase: Intestinal perforation Elevated urea or creatinine: Ruptured bladder

16 TRANSUDATES AND EXUDATES - Many pathologic conditions can cause a buildup (effusion) of serous fluid. - A general classification of the cause of the effusion can be accomplished by separating the fluid into the category of transudate or exudate.

17 TRANSUDATES AND EXUDATES - Exudates are produced by conditions that directly involve the membranes of the particular cavity, including infections, malignancies and from an inflammatory process. - Transudates also can be thought of as resulting from a mechanical process,

18 TRANSUDATES AND EXUDATES - A variety of laboratory tests have been used to differentiate between transudates and exudates, including appearance, specific gravity, total protein, lactic-dehydrogenase, cell counts, and spontaneous clotting.

19 TRANSUDATES AND EXUDATES - As can be seen using these criteria, one would expect a transudate to be a clear fluid with a specific gravity less than 1.015, protein less than 3.0 g per dl, and a lactic dehydrogenase below 200 IU.

20 TRANSUDATES AND EXUDATES -Traditionally, specific gravity and protein were considered to be the most valuable criteria for classification. -In recent years, the lactic dehydrogenase has replaced the specific gravity.

21 Laboratory Differentiation of Transudates and Exudate ___________________________________ Transudate Exudate ________________________________________________________ Appearance Clear Cloudy Specific gravity Total protein 3.0 g/dl Lactic dehydrogenase 200 IU Cell count 1000/µl Spontaneousclotting No Possible _______________________________________________