1 urinalysis and body fluids (serous fluids) dr. essam h. jiffri
Post on 20-Dec-2015
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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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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.
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SEROUS FLUIDS
- Normally only a small amount of serous fluid is present because production and absorption take place at a constant rate.
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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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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.
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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).
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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
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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.
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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.
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Summary of Serous Fluid Testing
Pleural Fluid
Normal appearance: Clear, pale yellowTurbidity: White blood cells and microorganismsBlood: Traumatic injury, malignancy, traumatic tapMilky: Chylous or pseudochylous material Neutrophils: Bacterial infectionLymphocytes: Tuberculosis, malignancyNormal glucose: Parallels serum glucoseLow glucose: Tuberculosis, rheumatoid- inflammation, malignancyLow pH: Tuberculosis, malignancy, esophageal ruptureElevated amylase: Pancreatitis
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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
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Summary of Serous Fluid Testing
Peritoneal Fluid
Normal appearance: Clear, pale yellowTurbidity: Peritonitis, cirrhosisBlood: TraumaNeutrophils: PeritonitisLow glucose: Tubercular peritonitis, malignancyElevated amylase: Pancreatitis, gastrointestinal perforationElevated alkaline phosphatase: Intestinal perforationElevated urea or creatinine: Ruptured bladder
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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.
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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,
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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.
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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.
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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.
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Laboratory Differentiation of Transudates and Exudate
___________________________________ Transudate Exudate
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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
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