Tareq Abadl: Not Every Rh-Positive or Rh-Negative Result is That Simple
Tareq Abadl, Medical Lab Specialist, shared a post on LinkedIn:
“Not every ‘Rh-Positive’ or ‘Rh-Negative’ result is that simple!
Most people think RhD typing is a clear yes or no — but in transfusion medicine, it’s not always that straightforward.
Some individuals have what’s called a weak D or other RHD variants.
This means the D antigen is present, but expressed at very low levels, structurally altered or reacts inconsistently in routine testing.
Because of this, standard serologic typing may give uncertain or misleading results.
Why does this matter?
In blood banking, especially during pregnancy, this distinction is critical.
The American Red Cross notes that weak or altered D expression can produce a serologic weak D phenotype.
The AABB recommends molecular (genotyping) testing when RhD results are unclear.
Why? Because management decisions can change.
- Weak D types 1, 2, and 3 – can be safely treated as RhD-positive.
- Other variants (like partial D) – may still form anti-D – managed as RhD-negative
Key clinical impact this directly affects:
- Rh immune globulin (RhIg) use.
- Blood transfusion selection.
- Risk of alloimmunization.
Without genotyping, patients may: receive unnecessary RhIg or be given Rh-negative blood unnecessarily (a limited resource).
Even donor testing is more detailed than people expect: The Canadian Blood Services confirms that first-time donors typed as Rh-negative are often retested for weak D to ensure accurate classification.
Newer Insight (Important): Recent practice is shifting toward
- Routine RHD genotyping in pregnant patients with weak D.
- Better standardization of interpretation across labs.
- Reducing variation between hospitals in RhIg decisions.”
Other posts featuring Tareq Abadl on Hemostasis Today.
-
Aug 11, 2026, 06:48Rishdha Roshad: What Happens to the Brain During Cardiopulmonary Bypass?
-
Aug 11, 2026, 05:53Isaac Okello: Strengthening Sickle Cell Advocacy in Uganda
-
Aug 11, 2026, 05:38Rami Unterman: A Simple New Biomarker for Fibrotic ILDs
-
Aug 11, 2026, 04:10Haroun Gajraj: CLaCS vs Sclerotherapy – What Does the Evidence Show
-
Aug 11, 2026, 02:54Tareq Abadl: The Ultimate Guide to Clinically Significant Antibodies
-
Aug 10, 2026, 17:35Chokri Ben Lamine: Balancing Holistic Care and Precision in Hematology
-
Aug 10, 2026, 17:14Anna Stanizzi: Patient Blood Management as a New Model of Personalized Care
-
Aug 10, 2026, 17:12Odong Christopher: New Research on Ischemic Stroke Prediction in Uganda
-
Aug 10, 2026, 16:58Jeff Szer AM: Advancing the Management of Paroxysmal Nocturnal Hemoglobinuria