Adapted from Boyce JM, Pittet D; Healthcare Infection Control Practices Advisory Committee; HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force: Guideline for Hand Hygiene in Health-Care Settings. Recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force. Society for Healthcare Epidemiology of America/Association for Professionals in Infection Control/Infectious Diseases Society of America., MMWR Recomm Rep 51(RR-16):1–45, 2002.

The efficacy of handwashing in reducing the transmission of microbial organisms has been demonstrated. At the very minimum, hands should be washed with soap and water (if visibly soiled) or by hand antisepsis with an alcohol-based handrub (if not visibly soiled) in the following situations:

1. After completing laboratory work and before leaving the laboratory

2. After removing gloves. The Association for Professionals in Infection Control and Epidemiology has reported that extreme variability exists in the quality of gloves, with leakage in 4% to 63% of vinyl gloves and in 3% to 52% of latex gloves.

3. Before eating, drinking, applying makeup, and changing contact lenses, and before and after using the bathroom

4. Before all activities that involve hand contact with mucous membranes or breaks in the skin

5. Immediately after accidental skin contact with blood, body fluids, or tissues

a. If the contact occurs through breaks in gloves, the gloves should be removed immediately and the hands thoroughly washed.

b. If accidental contamination occurs to an exposed area of the skin or because of a break in gloves, wash first with a liquid soap, rinse well with water, and then apply a 1:10 dilution of bleach (Table 6-1) or 50% isopropyl or ethyl alcohol. The bleach or alcohol is left on skin for at least 1 minute before final washing with liquid soap and water.

Table 6-1

Preparation of Diluted Household Bleach

Volume Bleach	Volume H₂O	Ratio	Sodium Hypochlorite
1 mL	9 mL	1:10	0.5%

Two important points in the practice of hand hygiene technique follow (see Box 6-1):

• When decontaminating hands with a waterless antiseptic agent (e.g., alcohol-based handrub), apply product to the palm of one hand and rub hands together, covering all surfaces of hands and fingers, until hands are dry. Follow the manufacturer’s recommendations on the volume of product to use. If an adequate volume of an alcohol-based handrub is used, it should take 15 to 25 seconds for hands to dry.

• When washing with a nonantimicrobial or antimicrobial soap, wet hands first with warm water, apply 3 to 5 mL of detergent to hands, and rub hands together vigorously for at least 15 seconds, covering all surfaces of the hands and fingers. Rinse hands with warm water and dry thoroughly with a disposable towel. Use the towel to turn off the faucet.

Specimen-Processing Protection

Specimens should be transported to the laboratory in plastic leakproof bags. Protective gloves should always be worn for handling any type of biological specimen.

Substances can become airborne when the stopper (cap) is popped off a blood-collecting container, a serum sample is poured from one tube to another, or a serum tube is centrifuged. When the cap is being removed from a specimen tube or a blood collection tube, the top should be covered with a disposable gauze pad or special protective pad. Gauze pads with an impermeable plastic coating on one side can reduce contamination of gloves. The tube should be held away from the body and the cap gently twisted to remove it. Snapping off the cap or top can cause some of the contents to aerosolize. When not in place on the tube, the cap should still be kept in the gauze and not placed directly on the work surface or countertop.

Specially constructed plastic splash shields are used in many laboratories for the processing of blood specimens. The tube caps are removed behind or under the shield, which acts as a barrier between the worker and specimen tube. This is designed to prevent aerosols from entering the nose, eyes, or mouth. Laboratory safety boxes are commercially available and can be used for unstoppering tubes or doing other procedures that might cause spattering. Splash shields and safety boxes should be periodically decontaminated.

When specimens are being centrifuged, the tube caps should always be kept on the tubes. Centrifuge covers must be used and left on until the centrifuge stops. The centrifuge should be allowed to stop by itself and should not be manually stopped by the worker.

Another step to lessen the hazard from aerosols is to exercise caution in handling pipettes and other equipment used to transfer human specimens, especially pathogenic materials. These materials should be discarded properly and carefully.

Additional Laboratory Hazards

It cannot be overemphasized that clinical laboratories present many potential hazards simply because of the nature of the work done. In addition to biologic hazards, other hazards in the clinical laboratory include open flames, electrical equipment, glassware, chemicals of varying reactivity, flammable solvents, and toxic fumes.

In addition to the safety practices common to all laboratory situations, certain procedures are mandatory in a medical laboratory. Proper procedures for the handling and disposal of toxic, radioactive, and potentially carcinogenic materials must be included in the safety manual. Information regarding the hazards of particular substances must be included as a safety practice and to comply with the legal right of workers to know about the hazards associated with these substances. Some chemicals (e.g., benzidine) previously used in the laboratory are now known to be carcinogenic and have been replaced with safer chemicals.

Decontamination of Work Surfaces, Equipment, and Spills

Sodium hypochlorite solutions are inexpensive and effective broad-spectrum germicidal solutions. Generic sources of sodium hypochlorite include household chlorine bleach. Concentrations of 1:10 to 1:100 free chlorine are effective, depending on the amount of organic material present on the surface to be cleaned and disinfected. Many chlorine bleaches (available at grocery stores) are not registered by the U.S. Environmental Protection Agency (EPA) for use as surface disinfectants and are unacceptable surface disinfectants. The EPA encourages the use of registered products because the agency reviews them for safety and performance when the products are used according to label instructions. When unregistered products are used for surface disinfection, users do so at their own risk. EPA-registered chemical germicides may be more compatible with certain materials that could be corroded by repeated exposure to sodium hypochlorite, especially the 1:10 dilution.

While wearing gloves, all work surfaces should be cleaned and sanitized at the beginning and end of the shift with a 1:10 dilution of household bleach. Instruments such as scissors or centrifuge carriages should be sanitized daily with a diluted solution of bleach. It is equally important to clean and disinfect work areas frequently during the workday and before and after each shift. Studies have demonstrated that HIV is inactivated rapidly after being exposed to common chemical germicides at concentrations much lower than used in practice. Diluted household bleach prepared daily inactivates HBV in 10 minutes and HIV in 2 minutes. Disposable materials contaminated with blood must be placed in containers marked “Biohazard” and properly discarded.

Hepatitis C virus (HCV), HBV, and HIV have never been documented as being transmitted from a housekeeping surface (e.g., countertops). However, an area contaminated by blood or body fluids needs to be treated as potentially hazardous and requires prompt removal and surface disinfection.

Strategies differ for decontaminating spills of blood and other body fluids, based on the setting. The cleanup procedure depends on the porosity of the surface and volume of the spill. The following protocol is recommended for managing spills in a clinical laboratory:

1. Wear gloves and a laboratory coat.

2. Absorb the blood with disposable towels. Bleach solutions are less effective in the presence of high concentrations of protein. Remove as much liquid blood or serum as possible before decontamination.

3. Using a diluted bleach (1:10) solution, clean the spill site of all visible blood.

4. Wipe down the spill site with paper towels soaked with diluted bleach.

5. Place all disposable materials used for decontamination into a biohazard container.

Decontaminate nondisposable equipment by soaking overnight in a dilute (1:10) bleach solution and rinsing with methyl alcohol and water before reuse. Disposable glassware or supplies that have come into contact with blood should be autoclaved or incinerated. Staff should receive training in environmental surface and infection control strategies and procedures as part of an overall infection control and safety program.

Disposal of Infectious Laboratory Waste

The control of infectious, chemical, and radioactive waste is regulated by a variety of government agencies, including OSHA and the U.S. Food and Drug Administration (FDA). Legislation and regulations that affect laboratories include the Resource Recovery and Conservation Act, the Toxic Substances Control Act, clean air and water laws, right to know laws, and HazCom (chemical hazard communication). Laboratories should implement applicable federal, state, and local laws that pertain to hazardous material and waste management by establishing safety policies. Laboratories with multiple agencies should follow the guidelines of the most stringent agency. Safety policies should be reviewed and signed annually or whenever a change is instituted. Employers are responsible for ensuring that personnel follow the safety policies.

OSHA has defined infectious waste as blood and blood products, contaminated sharps, pathologic wastes, and microbiological wastes. Infectious waste is packaged for disposal in color-coded containers and labeled as such with the standard symbol for a biohazard (Fig. 6-2).

Figure 6-2 Biohazard symbol. (From Rodak BF, Fritsma GA, Keohane EM: Hematology: clinical principles and applications, ed 4, St Louis, 2012, Saunders.)

Infectious waste (e.g., contaminated gauze squares and test tubes) must be discarded into proper biohazard containers with the following features:

1. Conspicuously marked “Biohazard” with the universal biohazard symbol

2. Universal color—orange, orange and black, or red

3. Rigid, leakproof, and puncture resistant. (Cardboard boxes lined with leakproof plastic bags are available.)

4. Used for blood and other potentially infectious body fluids, as well as disposable materials contaminated with blood or fluid

Disease Prevention

Immunization

A well-planned and implemented immunization program is an important component of a health care organization’s infection prevention and control program. When planning these programs, valuable resources are available from the Advisory Committee on Immunization Practices (ACIP) and the Hospital Infection Control Practices Advisory Committee (HICPAC). The characteristics of the health care workers employed and the individuals served should be considered, as well as the requirements of regulatory agencies and local, state, and federal regulations.

In their recommendations for the immunization of health care workers, ACIP and HICPAC identify those health care workers whose maintenance of immune status is especially important, which includes laboratory staff. Other individuals are recognized as being at risk for exposure to and possible transmission of diseases that can be prevented by immunizations. The ACIP-HICPAC recommendations are divided into the following three categories:

1. Immunizing agents strongly recommended for health care workers

2. Other immunologic agents that are or may be indicated for health care workers

3. Other vaccine-preventable diseases

All health care organizations should include the strongly recommended immunizations. To determine whether to include other immunologic agents, the incidence of the vaccine-preventable diseases in the community served needs to be reviewed. Also, comparing the demographics of the workforce pool with the disease pattern in the community will determine which of these immunologic agents is (are) indicated for the specific organization’s program. Other vaccines may not be routinely administered but may be considered after an injury or exposure incident or for immunocompromised or older health care workers.

The ACIP-HICPAC recommendations determine which vaccines to include based on documented nosocomial transmission and significant risk for acquiring or transmitting the following vaccine-preventable diseases:

Optional immunizations include hepatitis A, diphtheria, pneumococcal disease, and tetanus. Because health care workers are not at greater risk for acquiring these diseases than the general population, they should seek recommendations for these immunizations from their primary care provider.

Screening Tests

Purified Protein Derivative Tuberculin Skin Test

If recently exposed to an individual with active tuberculosis (TB) infection, a health care worker may not yet have a positive TB skin test reaction. The worker may need a second skin test 10 to 12 weeks after the last exposure to the infected person. It can take several weeks after infection for the immune system to react to this purified protein derivative (PPD, Mantoux) tuberculin skin test. If the reaction to the second test is negative, the worker probably does not have latent TB infection. Strongly positive reactors, with a skin test diameter more than 15 mm and symptoms suggestive of TB, should be evaluated clinically and microbiologically. Two sputum specimens, collected on successive days, should be investigated for TB by microscopy and culture.

QuantiFERON-TB Gold

QuantiFERON-TB Gold (QFT) is a blood test used to detect infection with TB bacteria. The QFT measures the response to TB proteins when they are mixed with a small amount of blood. Currently, few health departments offer the QFT. If your health department does offer the QFT, only one visit is required, at which time your blood is drawn for the test.

Although the most important strategy for reducing the risk of occupational HIV transmission is to prevent occupational exposures, plans for postexposure management of health care personnel should be in place. The U.S. Public Health Service has issued guidelines for the management of health care personnel exposure to HIV and recommendations for postexposure prophylaxis (PEP).^∗

These guidelines outline considerations in determining whether health care personnel should receive PEP and in choosing the type of PEP regimen. For most HIV exposures that warrant PEP, a basic 4-week, two-drug regimen is recommended. For HIV exposures that pose an increased risk of transmission, a three-drug regimen may be recommended.

Special circumstances are also discussed in the guidelines, including delayed exposure report, unknown source person, pregnancy in an exposed woman, resistance of the source virus to antiviral agents, and toxicity of PEP regimens. Occupational exposures should be considered urgent medical concerns.

Hepatitis B Virus Exposure

After occupational exposure to Hepatitis B virus (HBV), appropriate and timely prophylaxis can prevent HBV infection and subsequent development of chronic infection or liver disease. The mainstay of postexposure prophylaxis (PEP) is Hepatitis B vaccine. In certain circumstances, Hepatitis B immune globulin is recommended in addition to vaccine for added protection.

After skin or mucosal exposure to blood, the ACIP recommends immunoprophylaxis, depending on several factors. If an individual has not been vaccinated, hepatitis B immune globulin (HBIG) is usually given for temporary protection, i.e., 3 to 6 months. It should be administered within 24 hours if practical, and concurrently with hepatitis B vaccine postexposure injuries. Recommendations for HBV postexposure management include initiation of the hepatitis B vaccine series to any susceptible, unvaccinated person who sustains an occupational blood or body fluid exposure. Both passive-active PEP with HBIG and hepatitis B vaccination and active PEP with hepatitis B vaccination alone have been demonstrated to be highly effective in preventing transmission after exposure to HBV.

PEP with HBIG and hepatitis B vaccine series should be considered for occupational exposures after evaluation of the hepatitis B surface antigen (HBsAg) status of the source and the vaccination and vaccine-response status of the exposed person. The specific protocol for these measures is determined by the institution’s infection control division. Postvaccination testing for the development of antibody to HBsAg (anti-HBsAg) for persons at occupational risk who may have had needlestick exposures necessitating PEP should be done to ensure that the vaccination has been successful.

In cases of non-occupational exposure ^∗ to hepatitis B virus (HBV) through a discrete, identifiable exposure to blood or body fluids, the suggested CDC protocol is as follows: