A positive Direct Antiglobulin Test (DAT) indicates that the patient's own red blood cells are coated with antibodies or complement in vivo. This coating can cause problems primarily in the forward grouping (cell typing) part of ABO testing. When these antibody-coated red cells are mixed with the commercial antisera (anti-A, anti-B), the coating can cause non-specific agglutination or 'rouleaux' formation (stacking of cells) that mimics true antigen-antibody agglutination. This can lead to false-positive or uninterpretable forward grouping results. For example, a truly type O patient with a positive DAT might show weak, non-specific agglutination with both anti-A and anti-B, falsely suggesting type AB. To resolve this, the patient's red cells must be washed thoroughly with warm (37°C) saline to remove the bound antibodies before repeating the forward grouping.

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Zambia

• loveness Phiri – 745 pts

• Visual Pathway Lesions
• Positive and Negative Symptoms
• Hallucinations and Delusions
• Antipsychotic Medications
• Emergency: Environmental Emergencies