Infection Prevention Orientation Manual

Section 10: Laboratory

Leslie Teachout MT(ASCP), CIC
October 2014

Download a printable PDF Version of this section.

Objectives

At the completion of this section the Infection Preventionist (IP) will:

• Describe basic elements of laboratory that are pertinent to Infection Prevention and Control
• Identify and interpret laboratory tests which have an impact on infection prevention and control
• Become familiar and meet with laboratory department personnel (i.e. chemistry-which usually includes serology, microbiology, and hematology) and the Manager/Director
• Become familiar with the State of Wyoming Public Health Laboratory
• Become familiar with laboratory methods such as how test are performed, how to interpret results and normal values
• Become familiar with the Wyoming Department of Health Reportable Conditions and diseases, notifications times and phone numbers
• Determine who and IF the lab reports State reportable diseases and become familiar with their process of reporting.

Number of hours

• Key Concepts – 1 hours
• Methods – 2 hours

Required Readings

• Grota P, Allen V, Boston KM, et al, eds. APIC Text of Infection Control & Epidemiolo 4^th Edition. Washington, D.C.: Association for Professionals in Infection Control and Epidemiology, Inc.; 2014.
  • Chapter 25, Laboratory Testing and Diagnostics, by J Smyer
  • Chapter 108, Laboratory Services, by P Prinz Luebbert
• Information available in Appendices A, B and C
• Wyoming Infection Prevention Orientation Manual (WY IPOM), Section #11 Microbiology

Overview

The IP should view the laboratory setting from two perspectives: an employee health and safety perspective, and as an essential partner of IPs in the detection and characterization of pathogens. The IP in many other healthcare facilities such as ambulatory surgery, outpatient dialysis, and long term care will find this information helpful in networking, assuring quality reports, and answering questions with the Laboratory. Refer to the WY IPOM Microbiology Section #11 for more details on the identification of specific organisms.

Key Concepts

Most microorganisms (bacteria and fungus) are singe cells and exhibit characteristics common to all biological systems: reproduction, metabolism growth, irritability, adaptability, mutation and organization. In contrast, viruses are considered a prokaryote because they lack the characteristics of living things, except the ability to replicate, which they accomplish only in living cells. Therefore, the most commonly used test methods for the detection of viral diseases are blood tests and/or titers for an immunologic response also known as serology.

Serology is the scientific study of plasma serum and other bodily fluids and refers to the detection of antibodies (immune response) in the serum or titers.  Such antibodies are typically formed in response to an infection, against other foreign proteins (i.e. mismatched blood), or to one’s own proteins (i.e. autoimmune disease).

In addition to the microbiology sections of a laboratory, the hematology area performs the Complete Blood Count (CBC), hemoglobin and hematocrit, and the differential (diff). The CBC includes the white blood count (WBC). The hemoglobin and hematocrit tests determine red blood cells. The differential provides a percentage concentration of various cellular components of the white blood cells (neutrophils, lymphocytes, monocytes, eosinophils, basophiles, and platelets).  The results of these tests (CBC, WBC, hemoglobin, and hematocrit) will give information regarding the potential for a bacterial vs. viral infection.

Methods

The IP should become familiar with the laboratory tests needed to diagnose diseases and the types of organism which cause the diseases. The IP should understand the specific requirements for specimen collection and transportation in order to insure that the correct sample is collected and can be tested. If a sample is not collected, handled, or stored properly, testing may be refused by the laboratory. The testing of specimens not collected, handled or stored properly will cause results to be misleading, inaccurate, or entirely incorrect due to the breakdown of enzymes, overgrowth of bacteria, or for other reasons. The IP should have a relationship with either the in-house laboratory, or the reference laboratory with whom the facility is contracting.

Clinical Microbiology Laboratory Experience

The IP should spend time with a mentor in the laboratory including the sections of microbiology, virology/serology and hematology.

The Hospital Laboratory

Not all healthcare facilities have a laboratory in-house and must use an outside hospital laboratory or even a commercial laboratory for routine diagnostic services. However, the exercises below should be applicable to all facility types.

Wyoming Public Health Laboratory

The state public health laboratory is a great resource for IPs, laboratorians, and healthcare providers. Certain infectious diseases must be confirmed through the submission of a specimen or isolate to the Wyoming Public Health Laboratory (WPHL). Refer to the list of Reportable Diseases and Conditions in Wyoming in Appendix C. The most current version of this list can be accessed at: www.health.wyo.gov/phsd/epiid/reporting.html.

Microbiology

Specimen collection and transportation

Specimen collection and transport to the lab is an essential part of the culture process. All specimens should be collected aseptically and placed in a sterile container; some specimens may be placed directly into culture media (e.g., blood cultures, genital cultures). Special handling techniques may be necessary for some specimens such as those for anaerobic culture. Prompt delivery to the laboratory is essential to prevent the death of pathogenic organisms or the overgrowth of commensal organisms. Some specimens may be refrigerated (e.g., urine, stool, sputum) while others should be maintained at room temperature (e.g., genital, eye, or spinal fluid) while awaiting transport.

Testing for Bacteria

The IP should know the general and specialized methods used to detect and identify bacteria. Please refer to Appendix B for more detailed information.

Interpretation of Microbiology laboratory results

The IP should know how to submit laboratory results and interpret results. Please refer to Appendix A for tips and suggestions.

Common Microbiology Requisition Problems

Awareness of common problems in microbiology submissions will help the IP avoid them and determine areas for improvement. Common problems include the denial of testing, the in ability to accurately interpret results, or other issues.

Virology/Serology

Specimen collection and transport

The IP should know the protocol for specimen collection and transportation, testing and interpretation of results when a viral etiology is suspected or when the only test method available is serology.

Testing for Viruses

Unlike most bacteria, viruses are not complete cells that can function on their own. They cannot convert carbohydrates to energy, like bacteria and other living cells do. Viruses depend on other organisms for energy, and cannot reproduce unless they get inside a living cell. There are three categories of diagnostic tests for viruses: 1) direct examination of the specimen, 2) virus isolation (a.k.a. cell culture) and 3) serology (a.k.a. testing for the antibodies against the virus). Because cell cultures take a long time they are not used often. Serology forms the mainstay of viral diagnosis. Following exposure, the first antibody to appear is immune globulin M (IgM), which is followed by a much higher titre of immune globulin G. Detection of rising titres of antibodies between acute and convalescent stages of infection, or the detection of IgM in primary infection are techniques often used for diagnosis of viral infections. The IP should know these test methods.

Interpretation of virology/serology laboratory results

In addition to many of the pieces of information required for microbiology testing, there are several specific pieces of information important for virus testing.

Common Virology/Serology Requisition Problems

Awareness of common problems in virology submissions will help the IP avoid them and determine areas for improvement. Common problems include the denial of testing, the in ability to accurately interpret results, or other issues.

Hematology

The IP should become familiar with: the hematology area. The hematology laboratory performs the Complete Blood Count (CBC), hemoglobin and hematocrit, and the differential (diff). The CBC includes the white blood count (WBC). The hemoglobin and hematocrit tests determinate red blood cells. The differential provides a percentage concentration of various cellular components of the white blood cells (neutrophils, lymphocytes, monocytes, eosinophils, basophils, and platelets). The results of these tests will give information regarding the potential for a bacterial vs. viral infection.

Documentation and Reporting

Documentation and reporting is a large part of the IP’s and the laboratorian’s job. The laboratory must be able to provide documentation and report specific processes, and testing results to the IP. For example, the laboratory may be responsible for reporting quality assurance and quality control to the IP and the quality improvement team. The laboratory may be required to report certain microorganisms (e.g. drug-resistant organisms) or the results of specific tests (e.g. Hepatitis) to the IP as soon as available. It is essential for the IP to know the reporting mechanisms for the laboratory. The IP must know the WDH reportable conditions and diseases, notification times, and phone numbers.  Please see the list in Appendix C. Numerous institution-specific responsibilities exist for using, handling, and summarizing laboratory reports. Such responsibilities include those listed in Table 15.

Other Issues

Clinical laboratories have guidelines and standards to assure the information or test results they provide are performed correctly and are accurate. Two methods for assuring testing results are by adhering to the Clinical and Laboratory Standards Institute guidelines and by performing quality control checks.

Clinical and Laboratory Standards Institute

Clinical and Laboratory Standards Institute (CLSI) develops standards for antimicrobial susceptibility testing of bacteria isolates from clinical specimens.  The IPs need to know the CLSI guidelines. The CLSI standards guide laboratories in the use of breakpoints for antibiotic susceptibility testing; the most common method is the use of MICs (Minimal Inhibitory Concentration).  The standards guide has information on the appropriate antibiotics to report for a specific organism. For example Klebsiella species are naturally resistant to ampicillin, thus ampicillin susceptibility patterns should not be reported.  The information from the CLSI guide should be reviewed annually to assure the most accurate organism sensitivities are being reported.  These Standards can be found on the CLSI website clsi.org/standards/, purchased by the laboratory from CLSI, or obtained from the Wyoming Public Health Laboratory.

Quality Assurance/Quality Control

Laboratories assess quality daily to assure the tests are accurate and performing correctly.  Laboratory Quality Assurance (QA) encompass activities that enable laboratories to achieve and maintain accuracy and proficiency despite changes in test methods and the volume of specimens tested. A good QA system does four things:

• establishes standard operating procedures (SOPs) for each step of the testing process, ranging from specimen handling to instrument performance validation;
• defines administrative requirements, such as mandatory recordkeeping, data evaluation, and internal audits to monitor adherence to SOPs;
• specifies corrective actions, documentation, and the persons responsible for carrying out corrective actions when problems are identified; and
• sustains high-quality employee performance.

Ethics

Discuss with your ICP mentor the steps which have been taken at your facility to ensure the confidentiality of reports.

Resources

Helpful/Related Readings

• Bennett J and Brachman P, eds. Bennett & Brachman’s Hospital Infection 6^th Edition. Philadelphia, PA: William R Jarvis; 2014.
  • Chapter 11, The Role of the Laboratory in Prevention of Healthcare-Associated Infections, by MA Pfaller and DJ Diekema
  • Chapter 15, Multidrug-Resistanct Organisms: Epidemiology and Control, by MY Lin, RA Weinstein and MK Hayden
  • Chapter 22, Clinical Laboratory-Acquired Infections, by ML Wilson and LB Reller
• Bennett G, Morrell G, and Green L, ed. Infection Prevention Manual for Hospitals; revised edition. Rome, GA: ICP Associates, Inc.; 2010. Section 7: pages 11-13.
• Bennett G. Infection Prevention Manual for Ambulatory Care. Rome, GA: ICP Associates Inc.; 2009. Section 7: pages 9-11.
• Bennett G and Kassai M. Infection Prevention Manual for Ambulatory Surgery Centers. Rome, GA: ICP Associates, Inc.; 2011. Section 7: page 12
• Heymann D. Control of Communicable Diseases Manual. 19^th Washington, D.C.: American Public Health Association; 2008.
• Pickering L., et al, eds. Red Book: 2012 Report of the Committee on Infectious Diseases. 29^th Elk Grove Village, IL: American Academy of Pediatrics; 2012.
• Mandell G, et al, eds. Mandell, Douglas and Bennett’s Principles and Practice of Infectious Diseases. 7^th Edition. Philadelphia, PA: Churchill Livingstone Elsevier; 2010.
• Lautenbach E, Woeltje KF, and Malani PN, eds. SHEA Practical Healthcare Epidemiology (3^rd Edition). University of Chicago Press, Chicago, IL 2010
  • Chapter 8 Twenty-First Century Microbiology Laboratory Support for Healthcare-Associated Infection Control and Prevention, by LR Peterson and MO Wright
  • Chapter 9 Molecular Typing Systems, by JHafkin, L Chandler and J Maslow

Helpful Contacts (in WY or US)

• Leslie Teachout MT(ASCP), CIC, Infection Prevention at Riverton (307) 857-3552 and Lander (307)335-6442 Hospitals, teachout@lpnt.net, cellphone (406)570-9321
• Cody Loveland, MPH, Infectious Disease Surveillance Epidemiologist and HAI Prevention Coordinator, Wyoming Department of Health, 307-777-8634, cody.loveland@wyo.gov

Related Websites/Organizations

• Wyoming Department of Health, Public Health Laboratory: health.wyo.gov/PHSD/lab/index.html
• The Clinical and Laboratory Standards Institute: org/
• Wyoming Department of Health, Infectious Disease Epidemiology Unit, Healthcare-Associated Infection Prevention: health.wyo.gov/phsd/epiid/HAIgeneral.html
• Mountain-Pacific Quality Health – Wyoming: mpqhf.com/wyoming/index.php
• APIC Professional Practice Resources: apic.org/Professional-Practice/Overview

Appendices

Please see the downloadable PDF version of this section to view the following appendices:

Appendix A: Reviewing and Interpreting Culture Results
Appendix B: Important Notes for Wound, Blood, Urine and Sputum Cultures.
Appendix C: Wyoming Department of Health Reportable Diseases and Conditions

WIPAG welcomes your comments and feedback on these sections.
For comments or inquiries, please contact:

Cody Loveland, MPH, Healthcare-Associated Infection (HAI) Prevention Coordinator
Infectious Disease Epidemiology Unit,
Public Health Sciences Section, Public Health Division
Wyoming Department of Health
6101 Yellowstone Road, Suite #510
Cheyenne, WY  82002
Tel: 307-777-8634    Fax: 307-777-5573
Email: cody.loveland@wyo.gov