Kalyan Roy/ LinkedIn

Sep 26, 2026, 18:01

Kalyan Roy: Blood Group Chimerism as a Rare Cause of ABO Discrepancy

Kalyan Roy, Transfusion Medicine Specialist at Square Hospitals LTD, shared a post on LinkedIn:

”Chimera: A Hidden Dual Identity in Blood Group and Transfusion Medicine

Have you ever encountered an unexplained mixed-field agglutination during ABO typing?

One rare explanation is blood-group chimerism—the presence of two genetically distinct red-cell populations within the same individual.

Key causes include:

Laboratory clues:

Mixed-field reactions in ABO/Rh or other blood-group systems, unexpected phenotype–genotype discrepancies, and unusual serologic patterns.

Important differential diagnoses:

Recent transfusion, ABO subgroups, HSCT, fetomaternal hemorrhage, mosaicism, and technical/sample errors.

When unexplained:

Consider extended serology, flow cytometry, ABO genotyping, STR analysis, and—when appropriate—DNA comparison from different tissues.

Key message:

Not every mixed-field reaction is chimerism—but every unexplained ABO discrepancy deserves an explanation before blood is issued.”

Kalyan Roy: Blood Group Chimerism as a Rare Cause of ABO Discrepancy

ABO typing Blood group Health Hematology Hemostasis Hemostasis News Hemostasis Today Kalyan Roy Medicine Transfusion Medicine

'

Targeted Thrombolysis Beyond tPA

'

'

10 Posts Not to Miss This Week

'

Managing Thrombotic Risk in Pregnancy

'

Hemostasis Today