Blood sample characterization in immunohematology
Precise pipetting of 10 to 50 µl and dynamic flushing at up to 72 ml/min
Automated immunohematology analyzers are used for the characterization of blood samples. Typical applications include blood typing, Rh factor determination, antibody screening, and the testing of blood products prior to transfusion.
For analysis, small sample volumes of 10 to 50 µl are aspirated from blood, serum, or buffer samples and transferred to the corresponding reaction wells. The fluidic system is subsequently cleaned to prevent carryover between samples. The combination of precise sample handling and efficient flushing is essential for reliable analytical results.
What requirements does blood sample characterization place on fluidic systems?
Immunohematology analyzers must handle small sample volumes with high precision while ensuring sample integrity and process reliability.
Key requirements include:
- precise aspiration and dispensing of 10 to 50 µl
- high repeatability in sample handling
- reliable separation of sample and system liquid
- effective flushing to prevent sample carryover
- reliable detection of blockages
- compact integration into OEM analytical instruments
Particularly when handling blood samples, the prevention of sample carryover is essential for ensuring reliable and reproducible test results.
How is sample handling implemented in immunohematology analyzers?
The blood sample is first aspirated into a sample loop and subsequently transferred to the analytical process. An air gap separates the sample from the system liquid, ensuring that the blood sample never comes into contact with the pump itself.
The mzr-4622 micro annular gear pump is used to precisely deliver the system liquid during sample aspiration and dispensing. The same pump also performs the subsequent flushing of the sample loop at flow rates of up to 72 ml/min.
An integrated pressure sensor supports fluidic system monitoring and enables the detection of blockages, for example caused by whole-blood components in the sample path. For OEM integration, a version with electrical isolation between the motor and the pump head has been developed. This prevents electrical interference and allows the pump to be integrated into systems with capacitive liquid level sensing.
What benefits does this provide for immunohematology instrument development?
By integrating the micro annular gear pump, the analytical instrument can:
- precisely pipette small blood samples
- reliably separate samples and system liquid
- prevent sample carryover between analyses
- efficiently clean sample loops
- detect blockages at an early stage
- support long maintenance intervals and high instrument availability
This fluidic solution combines precise sample handling with efficient cleaning of the fluidic system and supports the long-term reliability of automated analytical instruments. As a result, it contributes significantly to reproducible results in modern immunohematology applications.