Korean J Blood Transfus.  2023 Dec;34(3):198-210. 10.17945/kjbt.2023.34.3.198.

Unexpected Antibody Identification Experienced by a Referral Laboratory for Medical Testing

• Kim BS

• KMID: 2549682
• DOI: http://doi.org/10.17945/kjbt.2023.34.3.198

Abstract

Background
We report the identification of unexpected antibodies by a referral laboratory during medical tests conducted on samples from small hospitals and clinics nationwide.
Methods
From June 2021 to March 2023, 1,097 results were identified using two gel tests incorporating antiglobulin and enzyme in parallel and conditional 4℃ and room temperature methods with autocontrols.
Results
A total of 1,034 cases of unidentified antibodies which correlated with autocontrol positivities present at any stage were investigated. Among them, unidentified single or mixed antibodies were seen in 63.5% of 386 autocontrol (＋) and 33.8% of 648 autocontrol (–) cases. From the total number of cases, 661 cases having identified single or mixed antibodies were recategorized into single-identified antibody cases, resulting in 819 such cases. The final distribution and confirmation stages were 501 (61.2%) in antiglobulin, 211 (25.8%) in enzyme, 98 (12.0%) at 4℃, and 9 (1.1%) at room temperature. Of these, in the NaCl/Enzyme stage, 136 (25.0%) of Rh and 52 (65.0%) of the Lewis series were confirmed and added to the antiglobulin stage and a strengthened reaction was observed in 277 (50.9%) cases of Rh and 14 (17.5%) of the Lewis series. At 4℃, the proportions of antibodies confirmed were 51 (56.7%) for M, 39 (62.9%) for P 1 , 7 (8.8%) for the Lewis series, and strengthened reactions were detected in M, S, and P 1 . The confirmed cases in the room temperature method were 4 in P 1 , 4 in Fy(b), and 1 in Xg(a).
Conclusion
The presence of antibodies which correlated with increased autocontrol positivities indicated an increased detection of unidentified antibodies. The antiglobulin and enzyme stage in parallel with conditional 4℃ or room temperature methods combined displayed a good capability to detect unexpected antibodies with a wide diversity and strong reactivity.

Keyword

Unexpected antibody; Referral laboratory; LISS/Coombs; NaCl/Enzyme