Urinalysis and Body Fluids CRg Unit 5 5 & miscellaneous handouts draft Composition Bacteria, Cellulose & other undigested foodstuffs GI secretions, enzymes, bile pigments Cells Electrolytes and water Indications for testing GI bleeding, Malabsorption syndrome, pathogenic bacterial or parasitic infections Indications for testing continued o Liver and biliary duct disorders Collection o Clean container, avoid contamination with urine or toilet water o Qualitative tests require only small amount of random sample o Quantitative / timed specimens, may require collection over several days. May require entire sample during the time period (72 hr fecal fat) or small amounts taken over several days (O& P) o Some tests require restrictions of diet (occult blood)
Laboratory procedures Color normal brown color due to presence of urobilin (from bacterial breakdown of urobilinogen) o See table 15-2, page 211. Strasinger Macroscopic Stool Characteristics Fecal leukocytes o methylene blue, Wrights or Gram stain may be used to visualize WBCs. o Can indicate pathogenic bacterial infection or ulcerative colitis Microbiology tests o Gram stain not much help. Stool full of gram negative rods (mostly E. coli.) o Cultures use selective media (restricts the normal flora and allows pathogens to grow) o Salmonella, Shigella, Campylobacter, o C. difficile, & certain pathogenic strains of E.coli Ova & Parasites Giardia Enterobius vermicularis (pinworm) Taenia sagenata Taenia solis D. latum H. nana.. tapeworms
Fecal Occult Blood Testing (FOBT) Occult blood - detection of GI bleeding (often associated with colorectal cancer) Two samples from 3 different stools for a negative Traditional testing o using Guaiac and ortho-toluidine to react with blood o Hydrogen peroxide oxidizes a colorless compound to for a blue color. o Based on pseudoperoxidase activity of hemoglobin Quickly being replaced by immunochemical test (more on this later) Occult blood Diet restrictions No red meats Turnips Horseradish Melons Raw broccoli, & cauliflower Other restrictions No aspirin or other non-steroidal antiinflammatory medications for @ 7 days prior to collections to prevent GI irritation iron supplements avoided for 3 days High Vitamin C levels will reduce peroxidase activity Summary.. False positive o Aspirin and anti-inflammatory meds o Red meat o Horseradish, raw broccoli, cauliflower, radishes, turnips, melons o Menstrual and hemorrhoidal contamination and negative causes False negative o Vitamin C > 250 mg o Iron supplements containing vitamin C View demonstration at http://www.operationalmedicine.org/ed2/video/hemoccult.mpg
Immunochemical fecal occult blood (ifobt) Hemoccult ICT Specific for globin portion of human hemoglobin Uses anti-human hemoglobin antibodies No dietary or drug restrictions Most sensitive to lower GI bleeding (patients with upper GI bleeding, such as ulcer would not react as blood has been digested) This test is quickly replacing the traditional fecal occult blood test! Fecal Fat steatorrhea Excess fat from fat malabsorption Qualitative methods o Oil red O or Sudan IV - stain feces and examine microscopically for large red fat droplets. Quantitative method o Use sodium hydroxide to chemically titrate the amount of fat 3 day collection (72 hours) Dietary requirements APT - fetal hemoglobin To determine whether blood found in newborn s vomitus or stool is their own, or from the Mom. Testing makes use of fact that baby blood (Hgb F) cells are resistant to lysing with sodium hydroxide & remain pink, while mom adult (Hgb A) cells lyse changing from the pink to yellow - brown.
Fecal enzymes Proteolytic enzymes, trypsin, chymotrypsin, and elastase I. Pancreatic insufficiency Trypsin dilutions of specimen placed on x-ray film (covered with gelatin). Determine dilution at which no gelatin is cleared / digested. Not sensitive Fecal electrolytes and osmolality aid in diagnosis of malabsorption syndromes Fecal carbohydrates. Increased carbohydrates in stool results in osmotic diarrhea (lactose is example) Use Clinitest, copper reduction. Bronchial Washings & Bronchoalveolar Lavage Fiberoptic bronchoscope placed in airway can be used to obtain specimen. Sterile saline infused, and retrieved for analysis Results may be as good as biopsy. macrophages (60-80%), lymphs, up to 10% neutrophils up to 21% eosinophils < 1 % bronchial epithelial cells, squamous cells Cultures
Other miscellaneous fluids. Nasal smears Hansel stain for eosinophils Cyst fluids cells, and organisms Tears eosinophils Breast milk eosinophils. always can culture them.