A patient presents with high cold agglutinin titer and automated hematology results showing elevated MCV, MCH, and MCHC with decreased RBC; agglutinates are noted. What is the recommended corrective step?

A patient presents with high cold agglutinin titer and automated hematology results showing elevated MCV, MCH, and MCHC with decreased RBC; agglutinates are noted. What is the recommended corrective step?

• A. Perform RBC, Hgb and Hct determinations using manual methods
• B. Perform the RBC determination by a manual method; use the automated results for Hgb and Hct
• C. Repeat the determinations using a microscope of diluted blood
• D. Repeat the determinations using a prewarmed microsample of diluted blood

Answer: (D)

Cold agglutinins cause red blood cells to clump together at room temperature, which disrupts automated counting and causes false readings like elevated MCV and MCHC with a decreased RBC count. The way to correct this interference is to dissociate the aggregates by warming the specimen and testing on a prewarmed, diluted sample. Using a prewarmed microsample of diluted blood ensures the cells are kept at body temperature during measurement, dissolves the agglutinates, and prevents reformation of clumps, giving accurate RBC counts and reliable indices. Manual methods or using automated results for some parameters don’t address the underlying clumping once the sample has cooled, and repeating with microscopy or delayed cooling can still leave agglutination affecting results. Warming the sample and diluting appropriately is the most effective corrective step to obtain true values.

Cold agglutinins cause red blood cells to clump together at room temperature, which disrupts automated counting and causes false readings like elevated MCV and MCHC with a decreased RBC count. The way to correct this interference is to dissociate the aggregates by warming the specimen and testing on a prewarmed, diluted sample. Using a prewarmed microsample of diluted blood ensures the cells are kept at body temperature during measurement, dissolves the agglutinates, and prevents reformation of clumps, giving accurate RBC counts and reliable indices.

Manual methods or using automated results for some parameters don’t address the underlying clumping once the sample has cooled, and repeating with microscopy or delayed cooling can still leave agglutination affecting results. Warming the sample and diluting appropriately is the most effective corrective step to obtain true values.