MODULE 8: LAB ASSISTING

• Laboratory glassware


  • Should be clean, sterile, and grease-free
  • Must not be just physically clean but should also be chemically clean
  • Should be inspected thoroughly, dried in a drying oven at 150 °C, capped using an aluminum foil, and finally placed in a closet cabinet for storage
• Removing grease from glassware

  1. Boil the glassware in a weak solution of sodium carbonate, acetone, or any fat solvent

  2. For silicone grease, soak the stopcock plug or barrel in warm decahydronaphthalene for 2 hours

  3. Drain, rinse with acetone, or use fuming sulfuric acid for 30 minutes

  4. Rinse off all of the cleaning agents
• Rinsing glassware


  1. Rinse using running tap water, distilled water or use a large bath of distilled water

  2. For test tubes, graduated cylinders, and flasks, allow the tap water to run into and over them. Then, partly fill each piece with water, shake, and empty for about 6 times

  3. For pipets, attach a piece of rubbing tubing to the faucet, then connect the delivery end to a hose to allow water to run through them
• Cleaning culture tubes


  1. Autoclave for 30 minutes at 121 °C (15 p.s.i. pressure)

  2. If there are media that solidify upon cooling, pour them out while the tubes are still hot

  3. Empty the tubes

  4. Brush with detergent and water

  5. Rinse with tap water thoroughly

  6. Rinse using distilled water

  7. Place the tubes in a basket and let them dry

  8. Do not plug until the medium is added when preparing culture tubes that are to be filled with a medium (sterilized by autoclaving)

  9. Sterilize both the medium and the culture tubes with one autoclaving

  10. Plug and sterilize the culture tubes in the autoclave before adding the medium if the culture tubes are to be filled with a sterile medium
• Cleaning dishes and culture bottles

  1. Sterilize and clean following the procedure for cleaning culture tubes

  2. Wrap them in heavy paper or place them in a petri dish can

  3. Sterilize the dishes and culture bottles using the autoclave or a dry-air sterilizer
• Cleaning pipets


  1. Place pipets with tips down in a cylinder or tall jar of water immediately after use

  2. Do not drop them into the jar because the tips may break or chip

  3. Place a pad of cotton or glass wool at the bottom of the jar to avoid breaking the tips

  4. Make sure that the water level is high enough to immerse most if not the whole pipet

  5. Drain and place in a cylinder or jar of dissolved detergent. Soak in a jar of chromic acid cleaning solution if exceptionally dirty

  6. After soaking, drain them. Run tap water over and through the pipets until you are sure that all traces of dirt are removed

  7. Soak the pipets in distilled water for at least 1 hour

  8. Remove them from the distilled water

  9. Rinse and dry the outside portion using a cloth

  10. Shake the water out of the pipets and let them dry
• Sterilizing and storing clean glassware

  1. Place the glassware in a large bucket or boiler. Add 1%-2% soap or detergent before letting it boil for 30 minutes

  2. Rinse with tap water, scrub with detergent, and rinse once again. Use an autoclave, large steam oven, or a similar equipment to sterilize the glassware

  3. Dry the glassware by hanging them on wooden pegs or air-drying in baskets with mouths downward or using an oven with drying temperatures below 140 °C

  4. Protect the clean glassware from dust by plugging them with cotton, corking, or placing a heavy piece of paper over the mouth and sealing them with tape before placing them in a dust-free cabinet
• Additional precautions for glassware

  • Examine the glassware for damage and discard any cracked or broken glassware in the proper disposal container
  • Clean and remove any residue including all tapes and labels
  • Use automatic cleaning apparatuses like laboratory washing machine, automated pipette, burette washers, etc., if available
  • Autoclave contaminated glassware to sterilize
  • Air-dry the glassware if it will not be used immediately
  • Store the glassware in the proper place after drying
• Cleaning and maintenance of laboratory work areas

  1. The surfaces and all pieces of equipment within the laboratory should be cleaned regularly and should comply with the operating procedures devised by the constitution

  2. The laboratory aide must document the cleaning and maintenance activities done using a laboratory logbook
• Cleaning materials used in the laboratory

  • 12% Lysol (phenolic disinfectant or other suitable mycobactericidal disinfectant)
  • 3.5% sodium hypochlorite solution or household bleach
  • Spray bottles
  • Personal protective equipment
  • Broom, mop, and bucket
• 1% sodium hypochlorite solution


  For daily cleaning. Add 10 mL of sodium hypochlorite solution to 1000 mL of water
• 70% ethanol


  To produce 1 liter, take 70 mL of absolute ethanol and add 300 mL of distilled water
• Lysol (5% phenolic solution)


  1 liter of 5% Lysol is produced by adding 450 mL 12% Lysol to 550 mL of distilled water
• Waste management plan components

  • Types of wastes that are expected to be generated in the laboratory
  • Responsibilities of the laboratory personnel
  • Management authorization (signatures)
  • Accumulation of wastes for disposal
  • Identification and inspection of waste storage areas
  • Waste classification and segregation
  • Record-keeping
  • Decontamination materials (storage of unused and spent decontamination materials)
  • Publicly-owned treatment works (POTW) disposal
  • Permits and reporting requirements
  • Waste neutralization requirements
  • Waste storage
  • Satellite requirements
  • Storage accumulation and date requirements
  • Primary containment
  • Waste shipment
  • Federal and state regulations
  • Waste container packaging and labeling
  • Arranging for shipment and preparation of shipment papers
  • Packaging requirements
  • Disposal options
  • Landfill (land-ban restrictions, acceptable wastes, packing requirements)
  • Incineration (acceptable wastes, packing requirements)
  • Health and safety for storage and transportation areas
  • Training requirements
  • Personal protective equipment (PPE)
  • Exposure monitoring
  • Plan implementation
  • Information accessibility by staff
  • Laboratory accountability
  • Audits
  • Record-keeping requirements
  • Requirement for review and updates (e.g., at least annually)
• Principles of green chemistry

  • Pollution prevention and source reduction
  • Recycling chemicals and recover energy from waste
  • Reuse, redistribute, and reduce materials, redistribute surplus chemicals, and reduce hazards
  • Incineration, land disposal, and other treatment methods
• Proper handling of laboratory-accumulated waste materials

  • A satellite accumulation which serves as a temporary storage for waste in the laboratory should be designated, maintained, and controlled by a competent laboratory personnel
  • Waste materials have different categories and corresponding safety precautions and follow an appropriate disposal method
• Good practices and basic requirements for the accumulation of waste

  • Collect hazardous or flammable waste solvents in containers pending transfer or disposal
  • Do not mix incompatible waste to avoid occurrence of heat generation, gas evolution, or other reactions
  • Always segregate wastes according to how they will be managed
  • Always observe the compatibility of containers and the waste contents
  • Provide a container (plastic or metal)
• Energy from waste


  • REUSE
  • REDISTRIBUTE
  • REDUCE
• REUSE, REDISTRIBUTE, AND REDUCE


  Materials, redistribute surplus chemicals, and reduce hazards
• Environmental fate of the waste

  • Incineration
  • Land disposal
  • Other treatment methods
• Proper handling of laboratory-accumulated waste materials

  1. Designate a satellite accumulation as temporary storage

  2. Waste materials have different categories and corresponding safety precautions

  3. Follow an appropriate disposal method
• Good practices and basic requirements for the accumulation of waste

  1. Collect hazardous or flammable waste solvents in containers

  2. Do not mix incompatible waste

  3. Segregate wastes according to how they will be managed

  4. Observe the compatibility of containers and the waste contents

  5. Provide a container for collection of liquid waste

  6. Label the waste containers

  7. Cap the waste containers after use

  8. Separately collect aqueous wastes from organic solvent wastes

  9. Place solid chemical wastes in a labeled container prior to disposal
• Laboratory waste materials in the satellite accumulation should not be kept for more than a year
• The amount of waste exceeding the limit should be managed accordingly within 3 days
• The Department of Health (DOH) launched the Health Care waste management program to provide guidelines to government and private hospitals and other facilities licensed by the Bureau of Health Facilities and Services (BHFS) on the proper collection, storage, segregation, transportation, and disposal
• The waste management manual recommends sorting waste into color-coded plastic bags or containers
• Urine collection methods


  • Regular voided
  • Midstream
  • Midstream clean-catch
  • Catheterized
  • Suprapubic aspiration
  • Pediatric
• 24-hour urine collection procedure


  1. Empty the bladder upon waking up

  2. Affix label on the container and write the time and date

  3. Discard output at the first hour and collect all urine for the next 24 hours

  4. Collect urine prior to bowel movement

  5. Take one last void at the end of the 24-hour collection period

  6. Seal the container before placing it in the cooler

  7. Arrange to transport the specimen to the laboratory
• Amniotic fluid


  A clear, colorless to pale-yellow liquid contained in the amniotic sac that is surrounding and cushioning the fetus during pregnancy
• The specimen is collected by the physician using transabdominal amniocentesis preferably 15 weeks after gestation
• The specimen collected in a sterile container should be protected from light and transported immediately to the clinical laboratory
• Cerebrospinal fluid (CSF)


  Clear and colorless and is obtained by the physician using a lumbar puncture or spinal tap
• The CSF is collected in THREE SPECIAL STERILE TUBES
• Collection of gastric fluid

  1. Pass a tube through the mouth/nose into the stomach after fasting

  2. Aspirate the sample to determine acidity before stimulation

  3. Administer a gastric stimulant intravenously after specimen collection

  4. Collect a series of specimens at timed intervals

  5. Place the collected specimens in sterile containers and label properly
• Nasopharyngeal secretions


  Collected by gently inserting a dacron or sterile cotton-tipped flexible wire swab through the nose and into the nasopharynx
• The swab is rotated and gently removed, then placed in a properly labeled sterile container containing the transport medium for immediate delivery to the laboratory
• Saliva


  The collection of saliva is easy and non-invasive because testing kits are available and many are point-of-care testing (POCT)
• The specimen needs to be frozen to ensure stability prior to delivery to the clinical laboratory
• Serous fluid


  The fluid is collected by the physician by aspiration and placed in tubes depending on the type of test
• Serous fluid collection tubes

  • Heparin or sodium fluoride tubes - chemistry tests
  • EDTA - cell counts and smears
  • Non-anticoagulated - biochemical tests
  • Heparin - blood cultures