Blood Bank Analyzers Buying Guide

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A blood bank is a place where recipient blood is typed (grouped) and screened for antibodies, and crossmatched for compatibility prior to transfusion with donated blood. 'The term 'blood bank' can also refer to a place where donor blood is collected, separated and stored. This guide is intended for immunohematologists working in the transfusion/compatibility testing department.

Blood banks face the same challenges as other clinical laboratories and this has shaped the direction of blood bank automation. The challenges vary depending on geography, but many laboratories have to deal with increased workloads, reduced staff levels, increasing cost of manual reagents, more rigorous patient safety initiatives, and tighter regulations.

In the transfusion laboratory, where manual methods have traditionally dominated, automation is helping to improve the safety of transfusion, increase efficiency and standardize work practices.


1. Why Automate?
2. Types of Blood Bank Analyzer
3. Column Agglutination Technique
4. Solid Phase Red Cell Adherence (SPRCA)
5. Erythro-Magnetic Technology (EMT)
6. Comparison Table of Available Technology
7. Planning Considerations
8. Testing Requirements
9. Future of Blood Transfusion Technology
10. Conclusion

Why Automate?

Blood bank automation was introduced in the 1960’s and many transfusion departments have already moved to automated analysis; however a large number of smaller laboratories and field sites still use manual methods. Tube testing has traditionally been the gold standard for ABO and Rh grouping, antibody identification and crossmatching, although this is increasingly less true of modern blood banks. The method is relatively simple and inexpensive, although the cost of manual reagents is rising.

The disadvantages of manual analysis include labor-intensive work, reduced efficiency, repetitive processes and a much lower safety record due to user error. Even small laboratories can benefit from automation, which frees up technical staff for other tasks that better utilize their skills.

Advantages of automation include:

  • Increased safety and decreased human error
  • Positive patient identification through specimen barcoding
  • Stable endpoint (not achieved with tube reactions)
  • Ability to archive results
  • Higher turnaround times due to batch testing
  • LIS interface for downloading requests and uploading results
  • Less labor-intensive
  • Tracebility of reagents, staff, and samples
  • Improved objectivity and reproducibility of test

Automatic crossmatching also offers reduced risk of incompatibility due to user error and/or incorrect labelling or specimen processing.

One of the main disadvantages of automation is the large start-up cost – automated immunohematology is expensive and can require a significant initial outlay. It may be possible to draw up a reagent rental agreement with your chosen supplier, where the manufacturer supplies the instrument and maintenance for free based on a projected workload, and the user agrees to a reagent contract.

Types of Blood Bank Analyzer

Automation of traditional tube agglutination methodology is difficult because of numerous factors, not least the lack of a stable endpoint – once the tube reaction has been resuspended, it cannot be viewed again. Manufacturers are now using three main types of technology: column agglutination technique (CAT), solid phase red cell adherence assay (SPRCA), and erythrocyte-magnetized technique (EMT).

Column Agglutination Technique

Manufacturers using CAT technology include Bio-Rad (ID-System), Ortho-Clinical Diagnostics and Grifols. CAT involves the use of plastic cards with 6-8 inbuilt microtubes, with a broad reaction chamber at the top and a clear gel/glass bead matrix at the bottom. Agglutinates are trapped within the gel matrix, and unsensitized cells form a button at the bottom of the microtube. There are two types of gel card: phenotyping for ABO and Rh – pre-filled with anti-sera, to which patient red-cell suspension is added; and AHG cards for IAT and DAT – pre-filled with anti-human globulin (AHG), to which patient plasma is added.

Blood Bank Image

Image: Erytra®, Grifols

There are advantages to transferring from manual tube agglutination to manual CAT. These include:

  • Standardization of tests – gel cards are pre-filled with reagent
  • Improved safety – clear, stable endpoint reactions
  • Cost-effective – less user intensive with less hands-on-time
  • Easy to use
  • Unaffected by lipaemic or light/moderate hemolysis of specimens
Blood Bank Image

Image: DiaMed ID-Card, Bio-Rad.

Manual use of gel cards requires the technician to pipette, incubate, spin and read the cards. But CAT technology allows for both partial and complete automation. Both Bio-Rad and Ortho-Clinical Diagnostics manufacture gel-stations that can automate pipetting, incubation, centrifugation, reading and interpretation. Full automation of CAT technology allows for a complete walk-away system and usually includes barcoding, bi-directional interfacing, STAT functionality, as well as continuous reagent and sample loading.

CAT can be used for grouping, cross-matching and antibody screening.

Blood Bank Image

Image: ProVue, Ortho-Clinical Diagnostics

Solid Phase Red Cell Adherence (SPRCA)

In SPRCA, the antigen/antibody is immobilized onto a solid medium, coating the base of a U-shaped microplate well. This is then allowed to react with free antigen/antibody. Microplates are coated with anti-sera for forward grouping, and RBCs for reverse grouping. The end point of the reaction is determined by the addition of red cells, which may be part of the antigen-antibody reaction, or may be added externally as indicator cells. SPRCA can also be adapted for crossmatching and platelet serology. Manufacturers that use SPRCA technology include Immucor and Bio-Rad (Tango Optimo).

Blood Bank Image

Image: Capture-R® Ready-Screen® , Immucor

Blood Bank Image

Image: TangoTM Optimo, Bio-Rad Diagnostics

Erythro-Magnetic Technology (EMT)

EMT involves the use of paramagnetic particles, which are fixed to the RBC surface either by adsorbtion or GPA glycoprotein binding. When a magnetic force is applied to the base of the plate, the RBCs migrate towards the magnet. The technique has the advantage that it completely eliminates the need for centrifugation. In forward grouping, iron chloride, bromelin and the RBC suspension are dispensed into the microplate well which has been pre-coated with anti-sera. After a short incubation period, the magnet draws the RBCs to the bottom of the plate. In reverse grouping, pre-magnetized RBCs are mixed with antisera in the well, and following incubation, the cells are also drawn to the plate base using a magnet. EMT can also be used for crossmatching and antibody screening.

Blood Bank Image

Image: QWALYS 3, Diagast.

Comparison Table of Available Technology

Technology

CAT

SPRCA

EMT

Conventional Tube Testing

Number of steps required

8-12

13-15

8-14

14-19

Washing step

Omitted

One washing step

Omitted

Multiple wash

Sample volume

Small

Small

Small

Larger volume required

Uniformity of testing in repeat testing

Yes

Yes

Yes

Depends on the skill of person performing the test

Clear and easily readable results

Yes

Yes

Yes

Variability in interpretation

Detection of IgG antibodies

Yes

Yes

Yes

Yes

Detection of IgM antibodies

Yes

No

No

Yes

Detection of weaker expression of blood groups

Yes

Yes

No

May detect

Suitable for lipaemic/hemolyzed samples

Yes up to 75mg/dl of free hemoglobin (Hb)

Yes

False positives with lipaemic/fibrinic samples

Difficult in hemolyzed samples

Amenable to all modifications of RBC and serum during testing

Some modifications may be possible

No (Bromelin treated cells are used for testing but not validated for other modifications)

No

Yes

Time taken to do ABO/D grouping (manual method)

Minimum of 20 mins

 

More than 30 mins

Fastest grouping method

Batch testing

More suited to batch testing in terms of time efficiency

More suited to batch testing in terms of time efficiency

More suited to batch testing in terms of time efficiency

Not suited to batch testing

Sensitivity for clinically significant antibodies

Better than CTT

Better than CTT

Better than CTT

Less than others

Sensitivity for CSAs antibodies

90-94%

Approx 97%

83.3-90.4%

Approx 43% (LISS-IAT)

Specificity

94.40%

94.30%

98.20%

98.60%

Table adapted from: Asian J Transfus Sci. 2012 Jul-Dec; 6(2): 140–144, Automation in Immunohematology, Meenu Bajpai, Ravneet Kaur, and Ekta Gupta

Planning Considerations

The needs of the blood bank will vary between each department, depending on how busy the laboratory is and the type of testing it carries out (donor screening, group and screening, crossmatching, antibody identification).

Technical specification factors to consider include:

  • Sample throughput
  • STAT functionality
  • Manual/ semi-automated/ fully-automated solution
  • Reagent monitoring/ on-board cool storage
  • Reagent shelf-life
  • Event logs
  • Result storage
  • Troubleshooting
  • Support service
  • Cost of consumables
  • Turnaround times
  • Instant access
  • Reflex testing options

General planning factors to consider include:

  • Specimen Entry
    You should also plan in advance whether you need to change the type of specimen tubes you will use, what type of barcodes you require, sample workflow as it enters the department and data inputting.
  • Physical Requirements
    In your planning, you will need to determine whether you have the physical space required for your chosen system, reagent and consumable storage, waste disposal and sample storage.
  • SOPs
    New standard operating procedures will need to produced, and staff training on the new equipment is essential. Your chosen vendor may supply this training, or you may need to draw up a training schedule and competence assessment for users.
  • Additional Costs
    It is vital to factor into any decision the additional costs involved in upgrading a laboratory system. Hardware and software requirements, reagent costs, cost for altering physical spaces, and storage costs (purchase of refrigerators, storage units etc) will all need to be considered.
  • Downtime
    Management of samples during downtime, scheduled or otherwise, must be considered. Your vendor may supply a back-up manual method, or a semi-automated back-up analyzer. Routine maintenance time should be factored into your SOP.
  • Quality Control
    How you will monitor QC should be planned, QC schemes assessed and competency assessments for users planned. Back-up systems will also need to be included in the daily QC schedule.
  • LIS
    Any system must be compatible with your existing LIS. It may be necessary to include your LIS provider in any negotiations with your chosen vendor. Installations are often delayed due to interfacing issues, and this should be taken into account when determining timescales.
  • User Reviews
    Getting feedback from other users (and not the manufacturers) is vitally important when making your purchasing decision. You can view system reviews on SelectScience, and if possible you should arrange to visit other laboratories that use your chosen analyzer so that you can get honest feedback and learn from the experience of others.

Testing Requirements

Your testing requirements will determine the analyzers that you are looking to purchase. Bio-Rad Tango, Grifols Erytra, Immucor Echo/ Neo, Ortho ProVue/AutoVue, QWALYS Diagast are all automated options for laboratories wishing to carry out group and screens, antibody identification and crossmatching on a single analyzer.

If partial automation is the goal, Ortho-Clinical Diagnostics, Grifols and Bio-Rad manufacture card readers, which offer manual labs the opportunity to take advantage of enhanced productivity and consistent results.

Future of Blood Transfusion Technology

The latest blood transfusion technologies have emerged in response to the need for improved safety, traceability, desire for standardization, and increasing workloads. The emergence of new technology has been enabled by advances in software and interfacing, so that many laboratories are now able to take advantage of these options.

Hemagglutination has limitations including the subjectivity of results, difficulty in phenotyping certain patients (e.g. those recently transfused, those with a positive DCT), and small antigen-negative donor red cell stock due to time intensity of hemagglutination methods. It can be very difficult to find compatible donor blood for patients requiring repeated transfusions due to infections, or chronic disorders such as sickle cell anemia or thalassemia.

Molecular diagnostics could overcome the limitations of hemagglutination, and the use of DNA-based tests to predict phenotype is increasing. Until now, molecular characterization has been laborious, time consuming and not suited to the transfusion laboratory. Modern DNA microarrays have the potential to allow for a high enough throughput to make molecular testing viable. To date this technology is not fast enough to be considered suitable for routine blood bank testing and there are no such systems approved for diagnostic use.

Matrix-Assisted Laser Desorption/Ionisation, Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) a new technology for molecular diagnostics, could have an impact on transfusion diagnostics in the future. MALDI-TOF MS generates a parent ion signature of all small and macro-molecules in the sample, including proteins, glycans, glycoproteins and nucleic acids. It is possible that this technology could be used for identifying clinically significant RBC antigens and corresponding atypical antibodies, and a collaboration between researchers in Switzerland and Germany has suggested that this could be a feasible method for high throughput blood group genotyping.1

Conclusion

The type of analyzer that you purchase depends on the testing requirements of your department, geographical availability of instruments, and budget. Modern automated systems for the blood bank increase throughput and efficiency while lowering safety risk to transfusion recipients and reducing potential for human error. Molecular diagnostics may help to further improve the safety of the transfusion department when used in conjunction with routine automated methodologies. As well as carrying out a thorough evaluation of products on the market, it is extremely valuable to learn from the experience of others. Many blood bank managers have already been through the process of automating their department, and they are now in a position to use their experience to benefit others.

1. Gassner C, Meyer S, Frey BM and Vollmert C. Matrix-Assisted Laser Desorption/Ionisation, Time-of-Flight Mass Spectrometry–Based Blood Group Genotyping—The Alternative Approach. Transfusion Medicine 2013;27 2-9.

Editor's picks

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Sonia Nicholas

Clinical Diagnostics Editor

Erytra® (Grifols)

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5 out of 5

"The stat function is very useful at night to get the analyzer started quickly. The bi-directional interfacing is excellent."
Rebecca Smith, The Ipswich Hospital NHS Trust


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Classic Plus ID-GelStation (Bio-Rad)

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4 out of 5

“It is easy to use and gets through the work quickly and has excellent customer service."
Jeby Jeyachandran, Queens Hospital



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NEO Blood Bank Analyzer (Immucor, Inc.)

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4 out of 5

“Easy to use system, some pipettor issues, great service team.”
Esther Schmidt, Boehringer Ingelheim Pharma



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Galileo ECHO Blood Bank Analyzer (Immucor, Inc.)

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4 out of 5

"Overall, I really like using the Galileo ECHO analyzer, we use the analyzer to do routine blood group good typing, although our current policy took out the use of week D testing."
Christina Bernier, University of Alaska Anchorage

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