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Cytogenetics

Laboratory Accidents

In the Cytogenetics laboratory, accidents are often the result of the manual nature of the work. Unlike highly automated sections of the lab, cytogeneticists manipulate open tubes, use sharps (scalpels/needles) for tissue processing, and handle large volumes of flammable fixatives. When an accident occurs, the immediate priority is always the safety of the individual, followed by containment of the hazard and administrative reporting

Percutaneous Injuries (Needlesticks & Sharps)

Percutaneous injury occurs when the skin is punctured by a contaminated sharp object. In cytogenetics, this most commonly involves hypodermic needles used to vent culture flasks, scalpels used to mince solid tissue biopsies, or broken glass Pasteur pipettes

  • Immediate Response
    • Put down the sharp: Place the item in a safe location to prevent further injury
    • Wash the wound: Immediately wash the area with soap and water for several minutes
      • Note: Do not: “milk” or squeeze the wound aggressively, as this may damage the tissue and increase blood flow to the area, potentially facilitating pathogen uptake. Do not use bleach or caustic agents on the skin
    • Bandage: Cover the wound with a sterile bandage
  • Risk Assessment
    • Hollow-bore needles: (e.g., syringes) carry the highest risk of transmission (HIV, HBV, HCV) because they contain a reservoir of blood inside the needle
    • Solid sharps: (e.g., suture needles or glass shards) carry a lower, but non-zero, risk

Mucous Membrane Exposure (Splashes)

Splashes occur when droplets of blood, amniotic fluid, or chemical reagents enter the eyes, nose, or mouth. This is a common risk during the “harvest” phase when supernatant is aspirated or during the “dropping” phase if a pipette is mishandled

  • Immediate Response (Eyes)
    • Proceed immediately to the Emergency Eyewash Station
    • Activate the hands-free mechanism (paddle or foot pedal)
    • Hold the eyelids open with thumb and forefinger to ensure irrigation reaches the entire eye and under the lids
    • Flush for a minimum of 15 minutes
  • Immediate Response (Mouth/Nose)
    • Rinse the mouth thoroughly with water (do not swallow) and spit repeatedly
    • Flush the nose with water

Dermal Exposure (Skin Contact)

This involves contact with hazardous chemicals (like Carnoy’s fixative or Formamide) or biological fluids on non-intact skin (cuts/abrasions)

  • Small Area: Wash immediately with soap and water
  • Large Area
    • Proceed to the Safety Shower
    • Remove contaminated clothing (lab coat, shoes, socks) while under the stream of water. Clothing can hold chemicals against the skin, exacerbating burns or absorption
    • Rinse for 15 minutes
    • Do not apply neutralizing agents (e.g., vinegar for alkali burns) to the skin unless specifically directed by a medical professional, as the reaction can generate heat

Spill Management (Biohazard)

When a culture flask drops or a harvest tube spills, the area is considered biohazardous

  • The Spill Protocol
    1. Alert and PPE: Warn coworkers. Ensure you are wearing gloves, a lab coat, and face protection
    2. Contain: Cover the spill with absorbent material (paper towels) to stop it from spreading
    3. Disinfect: Pour a disinfectant (typically 10% Sodium Hypochlorite/Bleach) over the paper towels. Pour gently to avoid creating aerosols
    4. Contact Time: Allow the bleach to sit for 20 minutes to penetrate the spill and kill pathogens
    5. Clean Up: Remove the soaked towels. If broken glass is involved, use mechanical means (forceps, tongs, or a brush and dustpan). NEVER pick up broken glass with your hands, even if gloved
    6. Final Wipe: Clean the surface again with disinfectant, followed by water to remove corrosive residue

Reporting & Post-Exposure Prophylaxis (PEP)

After the immediate physical response is complete, the administrative and medical response begins. This is a legal requirement under OSHA

  • Incident Report
    • The employee and supervisor must complete an incident report detailing:
      • When it happened
      • What happened (the procedure being performed)
      • The Source: Patient name/MRN (if known)
  • Medical Evaluation
    • The employee must report to Employee Health or the Emergency Department immediately
    • Time Sensitivity: If HIV prophylaxis (PEP) is required, it is most effective if started within 2 hours of exposure
  • Testing
    • Source Patient: Will be tested for HIV, Hepatitis B (HBsAg), and Hepatitis C (if consent is obtained/legally allowed)
    • Employee: Baseline testing is performed. If the patient is positive, the employee is monitored serially (e.g., at 6 weeks, 3 months, 6 months) to detect seroconversion

Accident Prevention (Root Cause Analysis)

The final step in managing an accident is preventing recurrence

  • Review Engineering Controls: Was the sharps container full? Was the centrifuge bucket not sealed?
  • Review Work Practices: Was the laboratory scientist rushing? Was the needle recapped (a violation)?
  • Action Plan: Retraining staff or purchasing safer devices (e.g., blunt-tip needles or retractable scalpels)