[The Simplest Scheme for Detection of "Asian-Type" DEL in Clinical Blood Transfusion Laboratories]

To explore the simplest scheme for detection of "Asian-type" DEL in clinical blood transfusion and its application effectiveness.

100 pregnant women who tested Rh(D) negative by the saline method were selected. Their blood samples were first confirmed Rh(D) negative by the indirect antiglobulin test (IAT), followed by Rh phenotyping. Micro-absorption-elution test was used to detect serological DEL type, and fluorescence quantitative PCR (qPCR) method was applied to detect RHD genotype. Based on the results of serological and genetic tests, RHD gene sequencing was performed on samples that might have variants or showed inconsistent results between the two detection methods.

Among 100 pregnant women initially screened as Rh(D) negative by the saline method, 58 were positive and 42 were negative for C antigen. The IAT results showed that 8 were positive and 92 were negative. For the 92 IAT-negative samples, results of the micro-absorption-elution test showed that 37 were positive and 55 were negative. Results of the qPCR detection showed that among the 100 samples, 32 cases were "Asian-type" DEL, 8 cases were weak D types (including 7 cases of weak D15 and 1 case of weak D25, all of which were IAT-positive samples), and 60 cases were Rh(D) negative. Among the 37 micro-absorption-elution-positive samples, 32 were detected as positive by qPCR; one negative sample detected by qPCR was confirmed as RHD*DEL2 variant by sequencing, while the other 4 samples were confirmed as true Rh(D) negative via retesting and sequencing. This confirms the presence of false-positive results in the micro-absorption-elution test.

The "Asian-type" DEL detection scheme, which involves first detecting C antigen, followed by micro-absorption-elution test, and then genetic testing for samples confirmed as Rh(D) negative by IAT, is time-saving, labor-saving, and easy to implement.