Kleihauer Testing and Flow Cytometry. A Comparative Study for Assessment of Feto-Maternal Haemorrhage

Area of Science:

• Medical Laboratory Science
• Immunohaematology
• Obstetrics and Gynaecology

Background:

• The Kleihauer test quantifies feto-maternal hemorrhage (FMH) to determine anti-D Immunoglobulin (Ig) dosage for RhD-negative women.
• Accuracy concerns exist for the Kleihauer test, with flow cytometry proposed as a more accurate alternative.
• Flow cytometry is not universally available in all laboratories performing FMH estimations.

Purpose of the Study:

• To assess the comparability of results from standardized Kleihauer techniques with routine hospital Kleihauer tests and flow cytometry.
• To evaluate the accuracy and consistency of the Kleihauer test in quantifying FMH.
• To determine the clinical utility of a standardized Kleihauer test versus flow cytometry for guiding anti-D Ig administration.

Main Methods:

• Analysis of 957 samples comparing routine hospital Kleihauer tests with a standardized Kleihauer test and flow cytometry.
• Samples were initially tested in referring hospitals, then sent to a central transfusion center for standardized testing.
• Standardized Kleihauer technique and flow cytometric analysis were performed on all samples at the Mersey Transfusion Centre.

Main Results:

• Significant variation in Kleihauer test results was observed, even with the same sample.
• A tendency to overestimate FMH size was noted, potentially leading to unnecessary anti-D Ig administration.
• A standardized Kleihauer test demonstrated value in estimating FMH size.

Conclusions:

• A meticulously performed standardized Kleihauer test is valuable for estimating FMH and guiding anti-D Ig dosage.
• Flow cytometry provides additional value for equivocal Kleihauer results or when large FMH is indicated.
• Standardization of the Kleihauer test technique is crucial for reliable FMH quantification and appropriate clinical management.