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Hematology

Safe Work Practices

Safe work practices, often referred to as “work practice controls” by OSHA, are specific procedures and behaviors that modify the manner in which a task is performed to reduce the likelihood of exposure to hazards. Unlike engineering controls (which isolate the hazard) or PPE (which barriers the worker), safe work practices rely entirely on the discipline and technique of the laboratory scientist. In Hematology, where the volume of blood specimens is high and the use of glass slides and chemical stains is frequent, adherence to these behavioral standards is the primary defense against infection and injury

Personal Hygiene & Behavior

The laboratory environment requires strict adherence to behavioral boundaries to prevent ingestion, inhalation, or mucosal absorption of hazardous materials. The distinction between “Clean Areas” (offices, breakrooms) and “Technical Areas” (the bench) must be absolute

  • Prohibited Activities: Eating, drinking, smoking, applying cosmetics or lip balm, and handling contact lenses are strictly prohibited in technical work areas. Food and drink must never be stored in refrigerators, freezers, or cabinets where blood or reagents are kept. This prevents the accidental ingestion of pathogens via hand-to-mouth contact
  • Mouth Pipetting: It is a cardinal rule of laboratory safety that mouth pipetting is never permitted. Mechanical pipetting devices (bulbs, thumb-wheel pipettes, or automated pipettes) must always be used
  • Hair and Jewelry: Long hair must be tied back to prevent it from contact with specimens, moving instrument parts (like the sample rotor on an analyzer), or open flames. Dangling jewelry should be avoided as it can catch on equipment or harbor infectious agents
  • Hand Hygiene
    • Hands must be washed with soap and water immediately after removing PPE (gloves) and before leaving the laboratory
    • If hands are visibly soiled with blood or Wright’s stain, alcohol-based hand rubs are insufficient; vigorous washing with soap and water is required
    • Scientists with dermatitis, cuts, or abrasions on their hands must cover these lesions with a water-resistant bandage prior to gloving to prevent pathogen entry

Specimen Handling & Aerosol Control

Hematology specimens are typically whole blood, which poses a risk of aerosolization when agitated or opened. Safe work practices are designed to contain these infectious droplets

  • Uncapping Tubes: When manually removing a rubber stopper (e.g., for a reticulocyte count or manual dilution), the “pop” can release a fine mist of blood. The laboratory scientist should cover the stopper with a 3x3 gauze pad and twist gently, directing the opening away from their face and others
  • Centrifugation
    • Tubes must be capped before centrifugation. Spinning open tubes generates massive aerosols
    • Carriers must be balanced to prevent mechanical failure
    • If a tube breaks during centrifugation, the centrifuge must be turned off and left closed for at least 30 minutes to allow aerosols to settle before opening. Cleanup requires forceps and disinfectant; broken glass must never be picked up by hand
  • Transport: Specimens must be transported in leak-proof primary containers placed within secondary containers (like biohazard bags with a ziplock seal). Requisition forms should be placed in the outside pocket of the bag, never inside with the specimen, to prevent contamination of the paperwork

Sharps & Glassware Safety

Hematology is unique in the clinical lab due to the high volume of glass slides used for peripheral blood smears and the use of capillary tubes for micro-hematocrits. These glass items are considered sharps

  • Needle Safety
    • Needles must never be sheared, bent, broken, or recapped by hand
    • If recapping is absolutely necessary (rare), a mechanical device or the one-handed scoop technique: must be used
    • Safety features on lancets and needles must be activated immediately upon withdrawal from the patient
  • Glass Slides: A common error is discarding broken or used glass slides into soft biohazard bags. Slides can puncture these bags and injure custodial staff. Glass slides must be disposed of in rigid, puncture-resistant sharps containers
  • Capillary Tubes: When performing micro-hematocrits, glass capillary tubes are fragile. Mylar-wrapped (plastic-coated) tubes are recommended to contain glass shards if breakage occurs. When sealing the tube with clay, the tube should not be pressed against the clay tray while holding the very end, as it may snap and puncture the glove; strictly follow the manufacturer’s sealing instructions

Chemical Handling (Stains & Reagents)

While biological hazards are the primary concern in Hematology, chemical hazards from stains and lyse reagents are significant. Safe practices are dictated by the Hazard Communication Standard (Right to Know)

  • Methanol: The fixative in Wright-Giemsa stain is typically high-concentration Methanol. It is toxic (blindness/death if ingested), flammable, and can be absorbed through the skin
    • Practice: Use in a well-ventilated area. Avoid skin contact. Store large volumes in a flammables safety cabinet
  • Secondary Labeling: If a reagent is poured from a bulk container into a smaller working container (e.g., a jar of stain for manual dipping), the secondary container must be labeled with the chemical name and hazard warnings (often using the NFPA diamond or GHS pictograms)
  • Safety Data Sheets (SDS): Formerly MSDS, these documents must be readily accessible (digital or physical) for every chemical in the lab. Staff must know where to find them to treat specific chemical exposures

Housekeeping & Decontamination

Maintaining a clean workspace is a proactive safety measure. Clutter increases the risk of spills and accidents

  • Routine Decontamination: Work surfaces must be decontaminated with an appropriate disinfectant (typically 1:10 dilution of bleach or an EPA-registered hospital disinfectant) at the beginning and end of every shift, and immediately after any spill of blood or OPIM (Other Potentially Infectious Materials)
  • Spill Response
    • Small spills should be blotted with absorbent material (paper towels) first to contain the fluid
    • Disinfectant should be flooded over the area (gently, to avoid splashing) and allowed to sit for the required contact time (usually 10-15 minutes for bleach) before final cleanup
    • Broken glass involved in a spill must be removed with a brush and dustpan or forceps, never gloved hands

Ergonomics

Ergonomic injuries are a significant occupational hazard in Hematology due to repetitive tasks. Safe work practices include adjusting the environment to the worker

  • Microscopy: Prolonged microscope use can cause neck and back strain
    • Practice: Maintain a neutral spine position. Adjust the chair height so feet are flat on the floor. Use armrests to support the elbows while focusing. Take frequent “micro-breaks” to stretch and refocus the eyes
  • Manual Differentials: The repetitive motion of tapping a manual cell counter can lead to Repetitive Strain Injury (RSI) in the fingers/wrist. Use electronic counters with light-touch keys or automated image analysis systems when possible to reduce physical strain