| Title | Inaccurate doses of R immune globulin after rh-incompatible fetomaternal hemorrhage: survey of laboratory practice. | | Author(s) | Ramsey G, College of American Pathologists Transfusion Medicine Resource Committee | | Institution | Northwestern Memorial Hospital Blood Bank, Northwestern University, Feinberg 7-301, 251 E Huron St, Chicago, IL 60611, USA. g-ramsey@northwestern.edu | | Source | Arch Pathol Lab Med 2009 Mar; 133(3):465-9. | | MeSH | Adult
Clinical Laboratory Information Systems
Competency-Based Education
Dose-Response Relationship, Drug
Drug Dosage Calculations
Female
Fetomaternal Transfusion
Health Care Surveys
Humans
Infant, Newborn
Pathology Department, Hospital
Pregnancy
Reproducibility of Results
Rh Isoimmunization
Rho(D) Immune Globulin
| | Abstract | CONTEXT: Rh(D)-negative women with a large fetomaternal hemorrhage (FMH) from an Rh(D)-positive fetus are at risk for anti-D alloimmunization if they do not receive adequate Rh immune globulin (RhIG). Determination of the adequate RhIG dose for these women is a critical laboratory procedure for protecting their future Rh(D)-positive children.
OBJECTIVE: To determine how often laboratories recommended an inaccurate dose of RhIG for excess FMH.
DESIGN: Nearly 1600 laboratories using the College of American Pathologists' proficiency testing for fetal red blood cell detection were surveyed to determine (1) their calculation method and (2) the number of RhIG doses recommended for a survey specimen, based on their measured percentage of fetal red blood cells. We surveyed nearly 1450 laboratories for their accuracy in determining RhIG dose, using 2 common calculation methods we provided.
RESULTS: The AABB Technical Manual method was used by 67% of responding laboratories. However, 20.7% of laboratories using this method would have recommended an inaccurate dose of RhIG--11.5% too much and 9.2% too little--for the level of FMH reported in the survey specimen. If all laboratories had used the common recommendation of 300 microg/30 mL of fetal blood present, 2% would have recommended RhIG doses too low for the volume of FMH they measured. In 3 of the 4 calculation exercises we provided, 20% to 30% of laboratories underestimated the necessary dose of RhIG.
CONCLUSIONS: Based on our surveys, some mothers with excess FMH may be receiving inaccurate doses of RhIG. Laboratories performing quantification of FMH should review their procedures and training for calculating RhIG dosage. | | Language | eng | | Pub Type(s) | Journal Article
| | PubMed ID | 19260751 |
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