Stability of immunohaematological reagents used for blood typing of recipients in the tube technique.

Background and objectives: The storage temperature of immunohaematological reagents generally ranges from 2 to 8°C, and they should be utilised at room temperature. This study aimed to analyse the stability of immunohaematological reagents used in ABO and RhD typing.

Methods: The evaluation encompassed the potency, specificity, and integrity of anti-A, anti-B, anti-D, RhD control sera, and A₁ and B red blood cells (RBC) reagents after long (8 h) and short (4 h) daily periods of exposure to room temperature (20-24°C), 5 days a week for 4 weeks. Additionally, the A₁ and B RBC reagents were exposed daily for 11 h and 30 min at room temperature, including 30 more minutes at room temperature with simultaneous homogenisation through equipment. For the control, an aliquot of each reagent was constantly stored at refrigeration temperature, while another was exposed to room temperature for 12 h daily. Tests conducted included reaction intensity, titration, and avidity for antisera, reaction intensity, free haemoglobin determination, and electrical conductivity for the RBC reagents.

Results: The antisera maintained the reaction intensity. The titre and avidity of the antisera satisfied the minimum Brazilian requirements after different exposure periods. A higher free haemoglobin concentration was noted in the RBC reagents subjected to room temperature and simultaneous homogenisation, although this did not affect the potency and specificity. The electrical conductivity average of the RBC reagent remained consistent.

Conclusion: The findings indicate that the immunohaematological reagents from a specific manufacturer are stable under the tested temperature, ensuring the quality of the results under these conditions.