URINALYSIS AND BODY FLUIDS (SEROUS FLUIDS)

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.

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.

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 < 1.015 > 1.015 • Total protein < 3.0 g/dl > 3.0 g/dl • Lactic dehydrogenase < 200 IU > 200 IU • Cell count < 1000/µl > 1000/µl • Spontaneous clotting No Possible • _______________________________________________