Investigation Toolkit: Transfusion-transmitted Infections (TTI)

The U.S. blood supply is safer than it has ever been. However, any bloodborne pathogen has the potential to be transmitted by blood transfusion. Transfusion-transmitted infections (TTIs) are infections resulting from the introduction of a pathogen into a person through blood transfusion. A wide variety of organisms, including bacteria, viruses, prions, and parasites can be transmitted through blood transfusions. The use of a standard donor screening questionnaire as well as laboratory tests help to reduce the risk of an infectious organism being transmitted by blood transfusion.

Task List

Every investigation is unique and your role as health department may change. In some instances, you may be responsible for contacting involved parties, securing donor testing, and identifying co-recipients. In other cases, the investigation may be handled primarily by the blood collection facility or the transfusion service, and your role will be to ensure that the key action items are accomplished in a timely manner.

Recipient(s) Initiated Investigation

Notify relevant partners (i.e., blood collection agencies, hospitals, CDC, other health departments)

1. Information on recipient
   (may be acquired from treating clinician, transfusion service, or patient interview)
   • Obtain:
     • State of residency
     • Date illness onset
     • Course of current illness
     • Past medical history, including underlying diseases
     • Treating clinician contact information
   • Confirm diagnosis if needed (may be performed at state public health laboratories, CDC, or commercial laboratories depending on suspected pathogen)
   • Evaluate patient history for potential exposures other than blood transfusion (i.e., residence in or travel to endemic area, laboratory accident, IVDU)
   • Obtain date and location (i.e., hospital, transfusion service) of recent transfusion(s)
     Note: If blood transfusions occurred in a different state, consider notifying the health department.
   • Check on availability of specimens (both pre- and post-transfusion) for further testing to rule-in/out donor-derived transmission
     Note: If recipient has received multiple transfusions, specimens from periods of time between transfusions can be used to narrow the window of suspicion. Specimens may be available at the transfusion service or at other hospitals the patient may have visited. The recipient may be asked to give a specimen for testing at the time a transfusion-transmitted infection is suspected, so at least that specimen should be available.
   • Request pre-transfusion specimens, if available, for testing to ensure this was not a preexisting infection.
     Note: If specimens are unavailable, medical records may contain information relevant to preexisting infections (i.e., fever of unknown origin)
   • Encourage adequate and appropriate treatment (treatment decisions should be determined by the recipient’s clinician, assist as needed).
2. Information from facility transfusion service(s)
   • Collect contact information for transfusion service and recipient’s current medical care team (e.g. attending clinician, primary care)
     Note: May be at different facilities.
   • Acquire unit numbers, type of blood component, and associated blood center(s) for each transfusion received.
     Note: Some recipients may have received many transfusions with blood from many donors given at multiple blood centers.
3. Information from blood collection facility(s)
   • Collect information for point of contact (POC) at the blood collection facility
   • Notify blood center of potential transfusion-associated infection and determine their SOP for donor contact and testing
   • Per usual procedures, blood center(s) may hold blood bag segments from the donations for testing and quarantine co-components from implicated units
   • Establish mechanism for receiving updates on donor testing with blood center(s) (or group that is performing the testing)
4. Donor(s)
   If potentially infected (e.g., seropositive) donor(s) are identified:
   • Recommend that the donor(s) see a health care provider for evaluation and treatment
   • If possible, conduct an interview with donor(s). Consider acquiring demographic information, travel history, outdoor activities, history of exposure(s) to the agent, and clinical manifestations consistent with infection.
   • Work with blood collection facility(s) to identify all recent donations and where the donations were shipped for the implicated donor(s). Identify possible contaminated products (RBCs, plasma, etc.) within appropriate window.
     Note: The length of time and types of components to consider varies by pathogen.
   • If blood bag segments are still available, arrange for testing by blood center collection facility (may also be performed at state public health laboratories, CDC, or commercial laboratories depending on suspected pathogen)
5. Co-Recipient(s)/Recipients of potentially contaminated donations if blood was transfused,
   • Investigate recipients of transfused co-components from implicated donation and other potentially contaminated donations from implicated donor(s).
   • Examine for laboratory evidence of implicated pathogen(s).
   • Consider signs/symptoms and other potential exposures in recipients.

Note: Testing for infections of unknown origin is available at CDC.

Donor Initiated Investigation

Notify relevant partners (i.e., blood collection agencies, hospitals, CDC, other health departments)

1. Basic information on donor
   • Date and locations (i.e., blood collection facility) of recent donation(s)
     Note: If donor has multiple donations, define time periods.
     Note: If state of residency is not where the investigation was initiated, consider notifying other health departments.
   • History of clinical manifestations consistent with infection
   • Pathogen-specific exposure history
   • Confirm diagnosis if needed (may be performed at state public health laboratories, CDC, or commercial laboratories depending on suspected pathogen)
   • Encourage adequate and appropriate treatment, if indicated (treatment decisions should be determined by the donor’s clinician, assist as needed).
2. Blood collection facility(s)
   • Collect contact information for point of contact (POC) at the blood center(s)
   • Notify blood center of potential transfusion-transmitted infection
   • Request that the blood center(s) hold retention segments from the donations for testing and quarantine components from donor
   • Request non-transfused components for testing
   • Obtain unit numbers and contact information for transfusion service(s) that received units
3. Facility transfusion service(s)
   • Collect contact information for transfusion service(s) at facilities where donor’s blood was sent and recipient’s medical care team (e.g., attending clinician, primary care)
   • Identify recipients of the donor’s blood components (usually done by the transfusion service). The recipient's physician should be notified of the transfusion event and asked to cooperate in testing and gathering further data on the status of the recipient.
     Note: This is usually done through the patient’s primary care physician; not the physician that ordered the blood transfusion. If the primary care physician cannot be identified, the local health department may need to contact the patient and arrange for testing.
   • If not conducted by the health department, schedule mechanism to receive results from transfusion service or group conducting recipient follow-up

Transfusion-transmitted Infections (TTI) Investigation Form

Recipient Investigation Form
This form is designed to assist investigators in collecting information relevant to transfusion-associated cases. These are not for reporting an outbreak of disease to the CDC. For reporting assistance, please refer to your State Health Department.

Donor Investigation Form
This form is designed to assist investigators in collecting information relevant to transfusion-associated cases. These are not for reporting an outbreak of disease to the CDC. For reporting assistance, please refer to your State Health Department.

Download the Recipient and Donor TTI Investigation Form [PDF – 6 pages]

Download the instructions for completing the investigation form [PDF – 8 pages]