Infection Preventionist Starter Kit: Laboratory and Surveillance
Infection preventionists (IPs) and clinical providers greatly rely on the microbiology laboratory to inform infection prevention practices as well as clinical decision making. Lab results can help detect emerging pathogens, multidrug-resistant organisms, and outbreaks in a facility as well as indicate types of precautions needed. A strong, ongoing partnership between microbiology laboratory professionals and IPs should remain a top priority in all infection prevention programs to ensure maximum patient safety and improve patient outcomes.
Specimen collection
Lab specimens must be handled properly to achieve the highest quality test result. This includes proper labeling, packaging, and prompt transportation to the laboratory at the proper temperature according to specimen type. Allowing specimens to remain at room temperature for long periods of time, or inappropriately placing certain specimens, such as spinal fluid, in a refrigerator can lead to erroneous results.
Review your facility’s policy for specimen collection. Observe staff collecting specimens such as urine or wound swabs to see if they are following proper procedure to ensure accurate and reliable lab results.
IP tip: Connect with the lab where your specimens are sent. Find out proper collection and transport requirements for each specimen type your facility routinely collects. If a provider requests an unfamiliar specimen, consult with the lab for collection and transport requirements prior to obtaining the sample.
Test types
Urinalysis is the study of urine. Urinalysis is typically done prior to urine cultures to help determine whether a pathogenic process is occurring. If so, a further urine culture may be warranted.
It’s also important that staff who collect urine samples understand the proper procedure for specimen collection. Two common methods of urine collection include clean catch or foley specimen.
Microbiology is the study of microorganisms. These tests help determine whether a microorganism is present. There are different types of microbiology tests available:
- Molecular tests sequence DNA or RNA for specific markers of disease. Nucleic acid amplification tests (NAAT) and reverse-transcription polymerase chain reaction (RT-PCR) are examples of molecular tests.
- Culture and sensitivity tests, sometimes called antibiotic sensitivity tests (AST), identify the organism(s) present in a clinical specimen. The sensitivity aspect of the test helps determine which antibiotics should be used for treatment. For each antibiotic tested, there will be a result of “resistant,” “intermediate,” or “susceptible.”
- Colonization or point prevalence screening (PPS) testing detects microorganisms that are not currently causing an infection but are present within the body and may pose a risk of transmission to others. Colonized patients or residents may also develop later infections with the organism due to its ongoing presence in the body.
Serology is the study of blood serum, including antigens and antibodies. These tests help determine whether an infection is occurring or has occurred in the past.
An antigen is any foreign substance that triggers an immune system response. The body’s immune response produces antibodies, which is a protein found in the blood.
IgG and IgM antibodies
IgG and IgM antibodies are frequently tested in the lab and are important for IPs to understand and interpret.
- IgM antibodies are the body’s first line of defense against an antigen. When the body starts to develop an immune reaction, the IgM antibodies are made first. Therefore, IgM antibodies indicate an active infection, or the acute stage of infection.
- IgG antibodies are produced later in the immune response. Therefore, IgG antibodies indicate that infection has been present for some time, or the convalescent stage of infection.
When IgM and IgG antibodies are circulating together, this can indicate a recurrent infection. Sometimes serology results will also include a “total antibody” result. Don’t be afraid to reach out to the lab if you need help understanding the test result you receive.
IP tip: A helpful way to remember the distinction between IgM and IgG antibodies is this alliteration: “The presence of IgM antibodies indicates the body is making antibodies. The presence of IgG antibodies indicates the body has already got the immunity to the infection.”
Examples of IgG and IgM results interpretation
Surveillance
Surveillance is a method of collecting data, analyzing intervention effectiveness by reviewing data, and taking appropriate action to reduce risks. Surveillance data can be used to track infections, detect clusters and outbreaks, identify emerging diseases, and initiate containment strategies. Surveillance data is also used to ensure compliance with federal and state regulations or mandatory reporting requirements.
Data analysis and reports should be shared with key members of the organization, such as the infection control committee and the quality assurance and performance improvement (QAPI) committee. Consider sharing this data with frontline care staff as well. Solicit their feedback if you notice trends or increasing infections. In addition, celebrate staff when infection prevention efforts are going well.
IP tip: Use data from your surveillance when reviewing facility policies, procedures, and protocols, including your annual infection prevention risk assessment.
- Outbreak: An outbreak is an increase over the expected occurrence of an event. For example, a single case of an unusual disease such as Legionella may constitute an outbreak. Outbreaks require prompt investigation.
- Incidence rate: Incidence rate is a measure of new cases arising in a population over a given period of time. This may be the same as the infection rate. .
Calculation: number of new cases in a given time period/population at risk of the disease in that time period X 1,000
- Infection rate: Infection rate is a measure of the frequency of an event in a defined population. This may also be referred to as the prevalence rate.
Calculation: number of infections in a given time period/population at risk of the disease in that time period X 1,000
Standardized infection ratio (SIR) (PDF): SIR is a risk-adjusted summary measure used to track healthcare-associated infections (HAIs) over time in National Healthcare Safety Network (NHSN). It compares the number of reported HAIs to the number predicted based on National Healthcare Safety Network (NHSN) baseline data and adjusts for several factors that may impact the risk of acquiring an HAI.
This measure allows for comparison to the national baseline of one. A SIR greater than 1 indicates more infections than would be predicted. A SIR less than 1 indicates fewer infections than would be predicted.
Calculation: observed HAIs/predicted HAIs
Process surveillance can include audits, such as hand hygiene or personal protective equipment audits or observations such as observing placement of invasive devices or high-level disinfection of equipment.
Outcome surveillance can be used for tracking and trending overtime. Specific surveillance criteria is used to standardize definitions. These include NHSN and McGeer (Word).
It’s important to use standardized infection criteria so that you can track and trend infection data over time. Some facilities also use their data to compare their infection rates with other facilities.
Information can be tracked on a log, electronic surveillance program, or spreadsheet. You may also wish to plot your data in a graph to show trends over time. This can be helpful in showing problem areas or even to celebrate successes of your program.
State and federal requirements may indicate a specific method or database (such as the Wisconsin Electronic Disease Surveillance System (WEDSS), NHSN) for tracking surveillance data.
Due to potential health impacts, any confirmed or suspected case of the diseases and conditions listed in DHS 145 Appendix A, must be reported promptly, per state statutes. Specific reporting guidance for each reportable condition can be found on the DHS disease reporting webpage.
Next steps for IPs
- Read the Association for Professionals in Infection Control and Epidemiology's (APIC) The Infection Preventionist’s Guide to the Lab (PDF).
- Determine how your facility receives lab results. Examples might be: paper/fax, electronic medical record (EMR) notification, passive receipt in EMR. How will you as the IP be notified of lab results, who takes next steps (reporting, isolation, etc.) if required?
- Determine how reportable diseases and conditions are reported to public health. Set up electronic reporting through WEDSS if your facility performs lab testing and would like to automate this process.
- To learn more about specimen collection and transport, complete the three-hour training course from APHL entitled “Specimen Collection, Handling, Transport, and Processing” You will need to register for a free account with APHL. You can also browse their other available courses that may be of interest to you. Some courses may offer continuing education credits.
Resources
Wisconsin HAI Prevention Program resources
- IP Lunch and Learn webinar: Laboratory Basics Part 1
Laboratory Basics: Part 1 slides (PDF)
- IP Lunch and Learn webinar: Laboratory Basics Part 2
Laboratory Basics: Part 2 slides (PDF)
Other resources
Wisconsin HAI Prevention Program resources
- Wisconsin HAI Data
- Resources for Using NHSN
- IP Lunch and Learn webinar: Infection Surveillance
Infection Surveillance slides (PDF)
Other resources
Questions about HAIs? Contact us!
Phone: 608-267-7711 | Fax: 608-266-0049
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