LEC 2 AND 3: OTHER NON-BLOOD SAMPLE

• Approximately 100 to 200 g of feces is excreted in a

  24-hour period.
• approximately 9000 mL of ingested fluid, saliva,

  gastric, liver, pancreatic, and intestinal secretions

  enter the digestive tract each day.
• Under normal conditions, only between 500 to

  1500 mL of this fluid reaches the large intestine,

  and only about 150 mL is excreted in the feces.
• Large gallon containers, similar to paint cans, are

  used for 24-, 48-, and 72-hour stool collections for

  fecal fat and urobilinogen; these specimens must

  normally be refrigerated throughout the collection

  period.
• Watery Consistency 


  Present in diarrhea
• Small, hard tools


  seen with constipation
• Slender, ribbon-like stools


  Which suggest obstruction of normal passage of

  material through the intestine.
• Black


  Upper GI bleeding

  Iron therapy

  Charcoal

  Bismuth (Antacids)
• Red


  Lower GI bleeding

  Beets and food coloring

  Rifampin
• Pale yellow, white, gray


  Bile duct obstruction

  Barium sulfate
• Green


  Biliverdin/ Oral antibiotics

  Green vegetables
• Bulky/Frothy


  Bile-duct obstruction

  Pancreatic disorders
• Ribbon-like


  Intestinal constriction
• Mucus- or blood streaked

  mucus

  Colitis

  Dysentery

  Malignancy

  Constipation
• Black

  Upper GI bleeding

  Iron therapy

  Charcoal

  Bismuth (Antacids)
• Red

  Lower GI bleeding

  Beets and food coloring

  Rifampin
• Pale yellow, white, gray

  Bile duct obstruction

  Barium sulfate
• Green

  Biliverdin/ Oral antibiotics

  Green vegetables
• Bulky/Frothy

  Bile-duct obstruction

  Pancreatic disorders
• Ribbon-like

  Intestinal constriction
• Mucus- or blood-streaked mucus

  Colitis

  Dysentery

  Malignancy

  Constipation
• Routine fecal examination

  macroscopic, microscopic, and chemical analyses
• Special containers with preservative are available

  for ova and parasite collection.
• Routine fecal examination includes macroscopic,

  microscopic, and chemical analyses for the early

  detection of gastrointestinal (GI) bleeding, liver

  and biliary duct disorders,

  maldigestion/malabsorption syndromes,

  pancreatic diseases, inflammation, and causes of

  diarrhea and steatorrhea.
• Normal fecal specimen contains: bacteria,

  cellulose, undigested foodstuffs, GI secretions,

  bile pigments, cells from the intestinal walls,

  electrolytes, and water.
• Annual testing for occult blood has a high positive

  predictive value for detecting colorectal cancer in

  the early stages.
• quantitative fecal analysis requires the collection of at

  least a 3-day specimen.
• The patient must maintain a regulated intake of fat

  (100 g/d) before and during the collection period.
• Guaiac-Based Fecal Occult Blood Tests


  most frequently used screening test for fecal

  blood.
• Guaiac-Based Fecal Occult Blood Tests


  based on detecting the pseudoperoxidase

  activity of hemoglobin
• CEREBROSPINAL FLUID


  Provides a physiologic system to supply nutrients to

  the nervous tissue, remove metabolic wastes, and

  produce a mechanical barrier to cushion the brain

  and spinal cord against trauma.
• CSF is produced in the choroid plexuses of the two

  lumbar ventricles and the third and fourth

  ventricles.
• In adults, approximately 20 mL of fluid is produced

  every hour. The fluid flows through the subarachnoid

  space located between the arachnoid and pia mater
• Body maintains a volume of 90 to 150 mL in adults

  and 10 to 60 mL in neonates.
• CSF is routinely collected by lumbar puncture

  between the third, fourth, or fifth lumbar vertebra
• Specimens are obtained by a physician; most often

  through lumbar puncture (spinal tap) or lumbar

  tap.
• CSF first recognized Cotugno in 1764.
• The specimen is collected in a large, pre-weighed

  container. Before analysis, the specimen is weighed

  and homogenized.
• Confirmatory test for steatorrhea
• STEATORRHEA (FECAL FAT)


  Absence of bile salts that assist pancreatic lipase

  in the breakdown and subsequent reabsorption of

  dietary fat (triglycerides) produces an increase in

  stool fat.