MLSP

• 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
  • Water
• 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.

  
• Specimen Collection


  1. Normally collected in clean, dry, wide-mouthed containers that should be sealed and sent to the laboratory immediately after collection

  2. Special containers with preservative are available for ova and parasite collection

  3. Preserved specimens can usually be kept at room temperature

  4. 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
• Macroscopic Screening: Color and Appearance


  • The first indication of GI disturbances can often be changes in the brown color and formed consistency of the normal stool
  • Appearance: watery consistency present in diarrhea; small, hard stools seen with constipation; and slender, ribbon-like stools, which suggest obstruction of the normal passage of material through the intestine

  
• Occult Blood


  Annual testing for occult blood has a high positive predictive value for detecting colorectal cancer in the early stages
• Guaiac-Based Fecal Occult Blood Tests


  Most frequently used screening test for fecal blood, based on detecting the pseudoperoxidase activity of hemoglobin
• Quantitative Fecal Fat Testing


  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. The specimen is collected in a large, pre-weighed container. Before analysis, the specimen is weighed and homogenized. Refrigerating the specimen prevents any bacterial degradation
• 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
• Cerebrospinal Fluid


  Major fluid in the body, 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
• Cerebrospinal Fluid Production 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
• Cerebrospinal Fluid Volume


  Body maintains a volume of 90 to 150 mL in adults and 10 to 60 mL in neonates
• Cerebrospinal Fluid Specimen Collection

  1. CSF is routinely collected by lumbar puncture between the third, fourth, or fifth lumbar vertebra

  2. Specimens are obtained by a physician; most often through lumbar puncture (spinal tap)

  3. Tube No. 1: Chemistry and Immunology

  4. Tube No. 2: Microbiology

  5. Tube No. 3: Hematology (Cell counts)

  6. A Fourth tube may be drawn for the microbiology lab

  
• Normal CSF Appearance


  Clear, Crystal-clear and Colorless
• Terminology for CSF Appearance

  • Crystal-clear, cloudy or turbid, milky, xanthocromic, and hemolyzed/bloody
• Cerebrospinal Fluid is collected to diagnose meningitis, subdural hemorrhage, and other neurological disorders
• Routine tests performed on CSF: cell counts, chloride, glucose, and total protein
• Semen Composition


  • Spermatozoa 5%
  • Seminal fluid 60% to 70%
  • Prostate fluid 20% to 30%
  • Bulbourethral glands 5%

  
• Normal Sperm Morphology


  • Normal sperm has an oval-shaped head approximately 5 µm long and 3 µm wide and a long, flagellar tail approximately 45 µm long
  • It contains a head, neckpiece, midpiece, and tail
• Semen Specimen Collection


  1. Collected and tested to evaluate fertility and postvasectomy

  2. When a part of the first portion of the ejaculate is missing, the sperm count will be decreased, the pH falsely increased, and the specimen will not liquefy

  3. When part of the last portion of ejaculate is missing, the semen volume is decreased, the sperm count is falsely increased, the pH is falsely decreased, and the specimen will not clot

  4. Specimens are collected following a period of sexual abstinence of at least 2 days to not more than 7 days

  5. Warm sterile glass or plastic containers should be given

  6. If the sample is collected at home, it must be kept warm and delivered to the laboratory within 1 hour

  7. Specimens should be collected by masturbation; only nonlubricant-containing rubber or polyurethane condoms should also be used to collect the specimen
• Semen Specimen Handling


  • When accepting a semen sample, it is essential that the phlebotomist record the time of sample collection, and the sample receipt, on the requisition form because certain parameters of the semen analysis are based on specimen life span
  • Sample should be kept at 37°C
  • A fresh semen specimen is clotted and should liquefy within 30 to 60 minutes after collection
  • Normal semen volume ranges between 2 and 5 mL
  • pH: 7.2 to 8.0
• Normal Semen Appearance


  • Normal semen has a gray-white color, appears translucent, and has a characteristic musty odor
  • Semen analysis for fertility evaluation consists of both macroscopic and microscopic examination. Parameters reported include appearance, volume, viscosity, pH, sperm concentration and count, motility, and morphology
• Synovial Fluid


  • Joint fluid, is a viscous liquid found in the cavities of the movable joints (diarthroses) or synovial joints
  • Hyaluronic acid contributes the noticeable viscosity to the synovial fluid
  • Clear, pale-yellow, viscous fluid that lubricates and decreases friction in movable joints
  • Normally occurs in small amounts but increases when inflammation is present
• Synovial Fluid Specimen Collection

  1. Synovial fluid is collected by needle aspiration called arthrocentesis

  2. Normal synovial fluid does not clot (usually it is collected in a syringe moisten with heparin)

  3. Turbidity is frequently associated with the presence of WBC

  4. Normal viscous synovial fluid resembles egg white

  5. Collected in tubes: EDTA or heparin tube for cell counts, identification of crystals, and Smear preparation; Sterile tube for culture and sensitivity; Nonadditive tube for macroscopic appearance, and immunology tests and to observe clot formation

  
• Serous Fluid


  • It provides lubrication between the parietal and visceral membranes
  • Pale-yellow, watery, serum-like fluid found between the double-layered membranes enclosing the pleural, pericardial, and peritoneal cavities
  • Lubricates the membranes and allows them to slide past one another with minimal friction
  • Normally present in small amounts, but volumes increase when inflammation or infection is present or when serum protein levels decrease
• Effusion


  Increased in fluid volume
• Serous Fluid Specimen Collection

  1. Aspiration procedures are referred to as thoracentesis (pleural), pericardiocentesis (pericardial), and paracentesis (peritoneal)

  2. Usually >100 mL is collected

  3. EDTA tube is used for cell counts and the differential

  4. Sterile heparinized or sodium polyanethol sulfonate (SPS) evacuated tubes are used for microbiology and cytology

  5. Chemistry tests can be run on clotted specimens in plain tubes or in heparin tubes
• Amniotic Fluid


  • Present in the amnion, a membranous sac that surrounds the fetus
  • Provides a protective cushion for the fetus, allow fetal movement, stabilize the temperature to protect the fetus from extreme temperature changes, and permit proper lung development
  • Amount of amniotic fluid increases in quantity throughout pregnancy, reaching a peak of approximately 800 to 1200 mL during the third trimester, and then gradually decreases prior to delivery
• Amniotic fluid can be analyzed to detect genetic disorders such as Down's syndrome, identify hemolytic disease resulting from blood incompatibility between the mother and fetus, and determine gestational age
• Amniotic Fluid Specimen Collection

  1. Preferably collected after 15 weeks of gestation (pregnancy) and is obtained by a physician using a procedure called transabdominal amniocentesis

  2. Maximum of 30 mL of amniotic fluid is collected in sterile syringes

  3. The first 2 or 3 mL collected can be contaminated by maternal blood, tissue fluid, and cells and are discarded

  4. Normal amniotic fluid is colorless and may exhibit slight to moderate turbidity from cellular debris, particularly in later stages of fetal development
• Alpha-fetoprotein (AFP)


  • An antigen normally present in the human fetus that is also found in amniotic fluid and maternal serum
  • AFP testing is initially performed on maternal serum, and abnormal results are confirmed by amniotic fluid AFP testing
  • Abnormal AFP levels: problems in fetal development (such as neural tube defects or the potential for Down's syndrome
• Fetal Lung Maturity


  • Can be assessed by measuring the amniotic fluid levels of substances called phospholipids, which act as surfactants to keep the alveoli of the lungs inflated
  • Results are reported as a lecithin-to-sphingomyelin (L/S) ratio
  • Lungs are most likely to be immature if the L/S ratio is less than 2
  • Amniotic fluid testing to assess fetal lung maturity may be ordered on or near the patient's due date and is often ordered stat when the fetus is in distress
• Amniotic Fluid Specimen Handling

  1. The specimen should be protected from light to prevent breakdown of bilirubin and delivered to the laboratory ASAP

  2. Specimens for chromosome analysis (cytology) must be kept at room temperature

  3. Specimens for some chemistry tests (gases) must be kept on ice
• Sputum


  • Mucus or phlegm that is ejected from the trachea, bronchi, and lungs through deep coughing
  • For the diagnosis or monitoring of lower respiratory tract infections such as tuberculosis (TB), caused by Mycobacterium tuberculosis
  • The microbe that causes TB is called an acid-fast bacillus (AFB), and the sputum test for TB is often called an AFB culture
• Preferred sputum specimen: First morning, at least 1 hour after meal
• • Xanthochromia - used to describe CSF supernatant that is pink, orange, or yellow
• Buccal swabs


  A less invasive, painless alternative to blood collection for obtaining cells for DNA analysis
• Buccal swab collection


  1. The phlebotomist collects the sample by gently massaging the mouth on the inside of the cheek with a special swab

  2. DNA is later extracted from cells on the swab
• Buccal swabs are often collected for legal purposes such as paternity testing, therefore follow strict COC protocol