Lab Safety – BMLS 301 Week 6

Injury Response Protocols

  • Follow a three-tier assessment whenever an injury occurs on campus, clinical site, or workplace.
    • Major injury
    • Involves the head, eyes, or requires emergency medical services (EMS)/external medical treatment.
    • Immediate action: Call 911911.
    • Minor injury
    • Manageable with the first-aid kit kept in student laboratories.
    • Blood/body-fluid exposure
    • Includes needle cuts, punctures from contaminated sharps, or splashes to eyes, nose, mouth, or broken skin.
    • Requires BOTH immediate first-aid AND professional medical evaluation.
    • Notify MLS instructor and, if applicable, clinical mentor as soon as initial care is finished.

Blood or Body Fluid Exposure Procedures

  • Step A — Immediate first aid
    • Needle-stick (parenteral) injury: Wash vigorously under running water with foaming/sudsy soap.
    • Apply antiseptic; bandage the site.
    • Mucosal/conjunctival exposure (mouth, nose, eyes): Flush copiously with water or sterile saline.
    • Eyes: Use eye-wash station for a minimum of 15 min.
  • Step B — Identify the source & pursue testing
    • Determine whose blood/body fluid caused the exposure.
    • For deep wounds or large fluid volume, request the source individual’s blood be tested for HIV, HBV, HCV (state laws & facility rules apply).
  • Step C — Begin prophylaxis promptly
    • Antiviral “standard of care” requires prophylactic therapy within 2 h when indicated (e.g., HIV exposure).
  • Step D — Notify supervisory chain
    • After first aid, alert MLS faculty, clinical mentor, or work supervisor immediately.

Laboratory Hazard Categories

  • Biological – pathogens, human tissues, blood & body fluids.
  • Mechanical – moving parts, centrifuges, glassware.
  • Chemical – corrosives, solvents, reagents.
  • Fire – open flames, flammable chemicals.
  • Electrical – un-grounded equipment, damaged cords.
  • Emphasis on cultivating a “culture of safety” because accreditation bodies (e.g., CAP, JCAHO, OSHA) scrutinize laboratory safety behavior.

Biological Hazards & Standard Precautions — Historical Context

  • 1985: CDC introduces Universal Precautions to protect against HIV & HBV.
    • Core idea: Treat all blood & selected body fluids as infectious; rely on gloves, gowns, masks, goggles.
  • 1996: CDC expands to Standard Precautions to address gaps (e.g., airborne TB, droplet influenza, contact MRSA).
    • Guideline now covers all body fluids, secretions, excretions, non-intact skin, mucous membranes; sweat is excluded unless visibly bloody.

Standard Precautions — Core Components

  • Hand Hygiene
    • Wash hands with soap & water or use alcohol hand sanitizer before & after every patient or specimen contact.
  • Surface Disinfection
    • Use manufacturers’ germicides or freshly prepared 10 % bleach.
  • Personal Protective Equipment (PPE)
    • Gloves when touching blood, body fluids, tissues, or contaminated surfaces.
    • Masks/goggles/face shields when splatter or spray is possible.
    • Dispose of needles in puncture-proof sharps containers; never recap.
    • Have barrier devices on crash carts to limit mouth-to-mouth resuscitation.
  • Spill Management
    • Clean immediately with 10 % bleach or approved disinfectant.
  • Reporting
    • Promptly report needle sticks, splashes, or other exposures.

Surface Disinfection — 10 % Bleach Solution

  • Household bleach: 5–6%5\text{–}6\% sodium hypochlorite.
  • Desired final concentration: 10%10\% of the stock bleach.
    • Example: To make 500 mL500\,\text{mL}, combine 50 mL50\,\text{mL} bleach + 450 mL450\,\text{mL} distilled water.
    • Rule: Add bleach to water (not water to bleach) to limit splatter.
  • Label with contents, concentration, date, and preparer’s initials.
  • Storage: closed, cool, dark; prepare fresh at least every 3 days.
  • Dilution notation: 1/101/10 or 1:91{:}9 (1 part bleach : 9 parts water). Dilution factor =10=10.

Specimens Covered by Standard Precautions

  • Blood & blood-tinged body fluids
  • Cerebrospinal fluid (CSF)
  • Serous fluids: pleural, peritoneal, pericardial
  • Semen; vaginal secretions; amniotic fluid; synovial fluid
  • Urine; feces; vomitus; sputum; saliva; breast milk
  • Nasal secretions; tears

Transmission-Based Precautions (Second Tier)

  • Apply when a patient is known or suspected to carry highly transmissible pathogens.
    • Airborne Precautions
    • Pathogens in droplet nuclei ≤ 5 μm5\,\mu\text{m} (e.g., TB, varicella).
    • Negative-pressure rooms; N95 respirator masks.
    • Droplet Precautions
    • Large droplets > 5 μm5\,\mu\text{m} (e.g., influenza, pertussis).
    • Surgical mask within 3 ft of patient.
    • Contact Precautions
    • Direct/indirect transmission (e.g., MRSA, C. difficile).
    • Gloves and gowns; hand wash after removal; masks generally not required.
  • These measures add to Standard Precautions; they do NOT replace them.

Hand Hygiene — Technique & Triggers

  • Hand washing is #1 defense against nosocomial spread.
  • Wash:
    • When hands are visibly soiled or potentially contaminated.
    • After every patient contact.
    • Before eating, drinking, smoking, applying cosmetics, inserting contact lenses.
    • Periodically during routine laboratory work.
    • After restroom use.
  • Proper method (use only designated clean sinks):
    1. Turn water on; wet hands.
    2. Apply liquid soap; scrub vigorously 20 s, focusing on nails & rings.
    3. Rinse from wrists to fingertips (downward flow).
    4. Dry with paper towel.
    5. Use towel to turn off faucet; discard in regular trash.
  • Hand sanitizers: acceptable only if hands are not visibly dirty; never superior to washing.

Personal Protective Equipment (PPE)

Lab Coats / Gowns

  • Must be long-sleeved and fully buttoned/closed.
  • Extra fluid-resistant disposable gowns for high-splash tasks.
  • Do NOT wear lab coats outside laboratory.
  • Change coat if visibly contaminated; use a fresh coat for any patient contact.

Gloves

  • Vinyl or nitrile for high-risk procedures (e.g., phlebotomy, handling infectious materials).
  • Latex as alternative but watch for allergies/skin irritation.
  • Select correct size: snug yet comfortable.
  • Wash & dry hands before donning; soiling/oils degrade glove integrity.

Decontamination Methods

  1. Sterilization
    • Kills all microbial life, including spores.
    • Techniques: heat, high pressure (autoclave), irradiation, chemicals, filtration.
    • Appropriate for inanimate objects only.
  2. Disinfection
    • Destroys pathogenic organisms but may not eradicate spores.
    • Physical (e.g., UV) or chemical (e.g., 10 % bleach, aldehydes, phenols, quats, iodophors, oxidizing agents, alcohols).
    • Many disinfectants are irritants; use PPE & ventilation.
  3. Antisepsis
    • Reduction/inhibition of microbes on living tissue.
    • 70%70\% isopropyl alcohol is common; doubles as skin disinfectant pre-phlebotomy.

Surface Decontamination Routine

  • Disinfect with 1/10 bleach or chemical germicide:
    • At start & end of each shift/lab session.
    • After completing procedures with blood/body fluids.
    • Whenever surfaces become visibly contaminated.
    • Immediately after any spill.
  • Contact times
    • HIV inactivation: 2 min.
    • HBV inactivation: 10 min.
    • Minimum bleach surface wet-time: ≥ 3 min (longer for heavy organic load).

Spill & Broken Glass Management

  • If glass or sharps present:
    • Flood spill area with 10 % bleach or germicide; cover with paper towels; wait ≥ 3 min (≥ ½ mL blood → extend time).
    • Gather a sharps container & bio-waste bucket.
    • Use forceps/tongs (never hands) to pick up sharps; place in sharps container.
    • Sweep tiny fragments onto rigid card; dispose in sharps container.
  • Absorb remaining liquid (protein interferes with disinfectant effectiveness).
    • Use paper towels or granular absorbent.
    • Discard all cleanup materials as biohazard waste.

Biohazardous Waste Disposal

  • Containers bearing the biohazard symbol (fluorescent orange/orange-red with contrasting lettering).

Biohazard Bags (Red/Orange)

  • For items requiring special processing.
  • Acceptable contents:
    • Blood tubes/vials; plastic pipettes contacting blood/body fluids; test tubes used with such fluids.
    • Paper items or lab mats saturated with body fluids.
    • Agar plates; fecal samples.
    • Full sharps or pipette keeper containers; plastic slides with blood.
  • Do NOT overfill: replace at ≈ 2/3 capacity. Twist-tie & place into biohazard box lined with red bag.
  • Inappropriate items (should go to regular trash unless heavily soiled):
    • Lightly soiled gloves or paper; paper towels from hand washing; emptied urine cups; pipettes used for urine only.

Sharps Containers

  • Rigid, puncture-proof, labeled; stationed on workbenches.
  • Required for:
    • Microhematocrit tubes; glass slides; DIFF-SAFE dispensers.
    • Used needles & lancets; broken glass; wooden applicator sticks.
    • Blood-contaminated plastic pipette tips.
  • Needles: activate safety device immediately after use. Only discard in sharps container.
  • Prevent overfilling; notify instructor when approaching capacity.

Ethical, Regulatory & Real-World Connections

  • OSHA Bloodborne Pathogens Standard mandates employer provision of PPE, HBV vaccination, and exposure-control plans.
  • CAP & CLSI standards integrate these practices into laboratory accreditation checklists.
  • Timely prophylaxis and accurate documentation of exposures is a patient-safety AND worker-safety obligation.
  • Proper segregation of biohazard waste reduces environmental impact and disposal costs.
  • Consistent hand hygiene and PPE use are proven to curb hospital-acquired infections (HAIs), safeguarding public health and minimizing healthcare costs.