December 2018

Ontario Transfusion Transmitted Injuries Surveillance System (TTISS-ON)

By: Joanne Duncan, HRM, MSc, CCRP, McMaster Centre for Transfusion Research, Hamilton ON


The Transfusion Transmitted Injuries Surveillance System (TTISS) is a national surveillance and monitoring system for the reporting of adverse reactions to blood products (blood components and plasma derivatives) run by the Public Health Agency of Canada (PHAC). Each province is responsible to collect and report aggregate data, submitted voluntarily, by hospital Transfusion Medicine Laboratories (TML) or those responsible for reporting transfusion reactions in each hospital. Ontario is the largest user of blood components, accounting for 35% of all transfusion activity in Canada (based on the percentage of units of blood components transfused). Currently TTISS-ON participating hospitals capture over 94% of the transfusion activity in Ontario, representing 123 hospitals. For the past 15 years, McMaster University has been the home of TTISS-ON, continuing to coordinate and develop the program. TTISS-ON is an integral part of the Canadian national hemovigilance system, as it is the only reporting agency that collects ALL transfusion reactions, whether or not they are related to the blood quality.


From 2013 to 2017 the number of red blood cells and plasma transfused has been declining in Ontario while the number of pooled platelets and cryoprecipitate transfused has increased. During this time, 1,095 moderate to severe reactions were reported to TTISS-ON with TACO being the most reported reaction at 31% (Figure 1).


Figure 1: 2013 – 2017 Reportable (to TTISS-ON) Transfusion Reactions in Ontario N=1,095


Non-reportable reactions that are not captured by the national system include febrile non-hemolytic, delayed serologic and minor allergic reactions but in Ontario these more minor types of reactions are captured by a sentinel site model. Sentinel sites are a core of Ontario hospitals that report all reactions and comprise approximately a third of all transfusion reactions and transfusions that occur in the province. These sites capture all reactions (reportable and non-reportable), enabling TTISS-ON to understand the complete burden of reactions from minor to severe. For the period 2013 to 2017 the sentinel sites reported a total of 2,445 reactions to transfused blood components and plasma derivatives: 498 (20%) fell into the moderate to severe category and were reported to PHAC; and 1,947 (80%) were classified as minor non-reportable category being captured through the sentinel site model (Table 1).


Table 1: Sentinel Site reporting of all reactions N=2,445

Type of Reaction Blood Components Plasma Derivatives Total
Non-Reportable to TTISS (minor) 1,747 200 1,947 (80%)
Reportable to TTISS (moderate to severe) 359 139 498 (20%)
Total 2106 339 2445


By knowing the number of blood components transfused during this period (847,605 units), and number of reactions that occurred to blood components, we can calculate frequency of these transfusion reactions by type in Ontario.


Table 2: 2013 -2017 Sentinel Site Transfusion Reactions and Incidence N=2,106

Type of Reaction Blood Components
Moderate to Severe (Reportable) n=359 (17 %)
Acute Hemolytic Reaction 16 1:52,975
Delayed Hemolytic Reaction 35 1:24,217
Bacterial Infection 6 1:141,268
Hypotensive Reaction 17 1:49,859
Post Transfusion Purpura (PTP) 1 1:847,605
Severe Allergic/Anaphylactic/Anaphylactoid 70 1:12,109
Anaphylactic Shock 4 1:211.901
Transfusion Associated Circulatory Overload (TACO) 156 1:5,433
Transfusion Associated Dyspnea (TAD) 7 1:121,086
Possible Transfusion Related Acute Lung Injury (TRALI) 12 1:70,634
TRALI 2 1:423,803
Other results of investigation 24 1:35,316
Unknown 10 1:84,761
Minor (Non-reportable) n=1,747 (83 %)
Febrile Non-Hemolytic Reaction 791 1:1,072
Delayed Serological Reaction 365 1:2,322
Minor Allergic Reaction 590 1:1,437
Total 2,106 1:402


TTISS-ON has made reporting of transfusion reactions easy and less confusing by providing a common online Canadian Adverse Transfusion Event Reaction (CATER) form that can be completed electronically and printed off for submitting to other regulatory agencies (CBS, plasma derivative manufacturers, and Canada Vigilance Program, Health Canada). To determine who to report a reaction to, TTISS-ON provides an Ontario Guide for Reporting Transfusion Reactions and an interactive online version. If your TML/Blood Bank reports transfusion reactions and are not already participating in TTISS-ON, register to become a member and obtain your login. “How to” instructional videos for entering and downloading your hospital’s data and making reports can be found on the TTISS-ON website. Look for our full 5-year report coming soon and download our TTISS-ON symptom reaction app from the app store. If you have any questions, contact Joanne Duncan, TTISS-ON Coordinator.


Bloody Easy Tech Assess: Basic – If you got this one wrong, you were not alone!

By: Lisa Mantifel, Regional Project Coordinator, ORBCoN


Launched in 2008, the Tech Assess program is an online educational tool for medical laboratory technologists (MLTs) to test their theoretical knowledge in eleven areas of transfusion medicine. This tool benefits MLTs, supervisors, laboratory managers and students in hospitals, blood services and post-secondary schools by aiding in documentation and assessment of knowledge in the field of transfusion medicine. This tool can serve as part of a laboratory competency assessment program.


The Tech Assess program is composed of eleven modules covering the core competencies in Transfusion Medicine and is offered at both the Basic and Advanced level. In addition, the program contains Solid Phase Techniques and Gel Techniques as optional and stand-alone modules that can be chosen within the basic level. New tests are released approximately every year with a selection of previously used questions and at least 20% new questions. Each new test is sent for external review and comment to technologists working in the field of transfusion medicine before release. This serves to validate the content as well as test out the wording of the questions to try and ensure they are clear and not misleading.


Previous year’s data on the top incorrectly answered questions in basic and advanced modules are reviewed each year by the ORBCoN working group. The questions that prove difficult for users are analyzed for issues with respect to:

  • Knowledge – does this question reveal a knowledge gap?
  • Misleading – is the question or are the answer options misleading or confusing?
  • Fair – is this question fair?
  • Is this question at the correct knowledge level (I.e. basic vs advanced)?

The five most challenging questions in Bloody Easy Tech Assess: Basic Competency 2017/2018 version will be discussed below with regards to their fail rate, the logic behind the answer and assess if the question is reasonable or not. The data shown below is from April 30th, 2018 to December 10th, 2018.


Question 1: Reporting Module – Basic Level

How long should records of tracking the final disposition of blood components be kept?

a) 10 years 
b) 50 years
c) Indefinitely
d) 1 month

In the most recent versions of national standards, record retention for final disposition of blood components was revised from ‘indefinite’ to 50 years (1) (2). The working group determined that the question was fair and reasonable as it addressed a knowledge gap. Therefore, the fail rate for this question was attributed to the fact that the users were not aware of the change in the Standards.

Question 2: Blood Group (ABO / Rh) Module – Basic Level

Interpret the following results:

a) Weak subgroup of A Rh Negative
b) Group O Rh negative, probable recent transfusion with Group A red cells
c) Group A Rh negative, probable recent transfusion with Group AB red cells
d) Group A Rh negative, probable recent transfusion with IVIG ✓

Problems with serum or plasma testing in this patient case is most likely the result of recent transfusion with IVIG which can contain ABO isoagglutinins (3). The working group assessed this question as a fair question as it tests the user’s concept application skills for ABO grouping interpretation. Selections a and b would not result in a strong reaction (4+) with anti-A, both options b and c would demonstrate mixed field reactions and option c would also show reactivity with anti-B. Therefore, the correct option is d. The fail rate on this question can be attributed to a knowledge gap. ABO interpretation is considered basic level competency.

Question 3: Antibody Screen – Gel Techniques Module

As mentioned above, solid phase and gel techniques are stand alone modules that the user can choose to complete. We have included this question from Gel Techniques in this article because many hospitals use gel methods, and therefore should have the basic knowledge of gel methods. Which statement most likely explains a mixed field reaction in a gel antibody screen?

a) Too much serum has been added to the gel tube
b) b) The patient has been transfused with a different blood group of RBCs
c) There is likely an anti-Sda present
d) May be caused from clots in a serum sample ✓

Clots, particulates or other artifacts may cause some RBCs to be entrapped at the top of the gel that may cause an anomalous result in a negative test. Clotting issues may be minimized with the use of EDTA plasma (4). The user must be aware that the cells present in a gel antibody screen (i.e. testing patient serumor plasma) are commercial cells, and therefore do not have a mixed cell population. They are also not used for cell grouping (choice b), as this test uses patient plasma or serum only, not their RBCs. Anti-Sda reacts at room temperature and is not considered clinically significant. Gel method does not usually detect anti-Sda.

The fail rate of this question can be attributed to the wording of the question. The question infers a true mixed field presentation versus a clot in the sample mimicking a mixed field. The question should be reworded, for example:

“Which statement most likely explains an appearance of a mixed field reaction in a gel antibody screen?” or,

“Which occurrence is most likely misjudged or misinterpreted as a mixed field reaction in a gel antibody screen?”

This question will be flagged for revision during the next Tech Assess review.

Question 4: Compatibility Testing Module – Basic Level

A nurse just called to request additional RBC units for a patient for whom you performed compatibility testing on 4 days prior. The patient has only had 1 RBC transfusion which was 2 days ago. The patient now requires 2 more units because of a bleed. What is your most appropriate course of action?

a) Use the pretransfusion sample from 4 days ago ✓
b) Inform the nurse that a new sample must be obtained
c) Request more information as to why the request for 2 more units is needed
d) See if any PST samples were drawn from the morning run that may be used

The correct answer is A. Recipients who have been transfused with a blood component containing red cells or pregnant within the preceding three months, or if the history of transfusion or pregnancy is uncertain or unknown, the blood sample for compatibility testing shall be collected within 96 hours prior to transfusion (1) (2). The original blood sample may be used to crossmatch additional units after transfusion for up to 96 hours (1). The fail rate on this question can be partly attributed to a knowledge gap however, the wording could be misleading as it does not make it clear that the patient had not been transfused prior to this sample being drawn. This question will be reworded to clarify that point the next time it is used.

Question 5: Quality Assurance Module – Basic Level

What is the acceptable shelf life of a unit of red cells, stored at 1°C to 6°C if the seal has been entered?

a) 4 hours
b) 6 hours
c) 24 hours ✓
d) 48 hours

The correct answer is C. An open system of RBCs must be stored at 1-6°C and used within 24 hours or be discarded. Refrigeration of the opened unit is essential and can no longer be used after 24 hours. This is to prevent the possibility of bacterial contamination and proliferation in the unit due to introduction of air when the unit was entered. If the unit is stored at room temperature, it is only acceptable to use it within 4 hours.

“If the sterile seal on a system containing blood components is breached at any time during processing, the system shall be treated as an open system from the time the breach occurred. In an open system, blood components stored at 1 to 6°C shall be given a reduced expiration time of 24 h (1).”

This question is fair, and this standard ensures the safety of the RBC unit. The fail rate identifies a knowledge gap.

If you have any question, comments or feedback on these questions, or any resource, please contact ORBCoN here or at


  1. CSA. CSA Z902-15 Blood and blood components: Canadian Standards Association; 2015.
  2. CSTM. Standards for Hospital Transfusion Services Version 4: CSTM; 2017.
  3. AABB. Technical Manual 19th Edition Fung MK, Eder AF, Spitalnik SL, Westhoff CM, editors.; 2017.
  4. Micro Typing Systems, Inc. Instructions for use MTS anti-IgG Card Florida: Ortho-Clinical Diagnostics Company; 2008-2016.