Ni Kadek Mulyantari, I Putu Yuda Prabawa, I Nyoman Gde Sudana

Concordance of blood group testing results using column agglutination test (Gel Test) and tube test method at blood transfusion services, Ngoerah Hospital, Bali

Introduction

Concordance of blood group testing results using column agglutination test (gel test) and tube test method at blood transfusion services, ngoerah hospital, bali. Compares gel and tube blood group testing at Ngoerah Hospital, Bali. Finds 100% ABO interpretation concordance, supporting gel test implementation for transfusion services.

Abstract

Background: Blood group testing is a mandatory component of pre-transfusion testing performed prior to blood administration to patients. The tube test method is considered the reference method; however, it has several limitations. Some of these limitations may be addressed by the column agglutination test (gel test) method. The development of the gel method for blood group testing still requires validation and assessment of its concordance with the reference method. This study aims to evaluate the concordance of blood group testing results using the column agglutination test (gel test) method prior to its implementation in clinical service at the Blood Transfusion Unit of Ngoerah Hospital, Denpasar, Bali. Methods: This was a diagnostic (method-comparison) study conducted to assess the concordance of blood group testing results between the tube test method as the reference method and the gel test as an alternative method for blood group determination. The study was carried out at the Blood Transfusion Unit of Ngoerah Hospital from November to December 2024, involving 36 blood samples from patients requiring blood transfusion. Agreement was assessed at two levels: concordance of final ABO interpretation and concordance of agglutination grade for each reagent. Results: All 36 samples were obtained from adult patients with various diagnoses; approximately 60% were from the internal medicine department, and the remainder from surgical, obstetrics and gynecology, and intensive care units. The distribution of blood groups comprised 17 patients with group B, 13 with group O, 4 with group A, and 2 with group AB. The tube and gel methods demonstrated 100% concordance in ABO interpretation, with no interpretive discrepancy. Forward grouping (anti-A, anti-B) reactions were uniformly negative or 4+ in both methods. All grade differences were confined to reverse grouping: reactions of A cells with patient plasma showed concordant grades in 75.0% of cases and B cells in 77.8% of cases. Across both reverse-grouping reagents, 3 samples showed a weaker grade and 15 a stronger grade by the gel method compared with the tube method. Conclusions: Blood group testing by the tube and gel methods showed complete (100%) concordance in ABO interpretation. Differences were confined to agglutination grade in reverse grouping and did not affect ABO assignment. The gel method may be considered for implementation or as a confirmatory method given its interpretive concordance and practical advantages; the reverse-grouping grade differences should be interpreted with caution and evaluated further in larger studies.

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