title: False negative factor V Leiden assay following allogeneic stem cell transplant.
abstract: We report a case where a phenotypic test (an activity assay for activated protein C resistance) correctly indicated that the patient had an abnormality, whereas the initial genetic test (a PCR-based DNA assay used to detect the mutation in the FV gene) incorrectly indicated that the patient did not. The apparent false negative result of the DNA-based test was due to the use of peripheral blood leucocytes for DNA analysis. The patient had undergone a stem cell transplant several months before, and the leucocytes in her blood were derived from the stem cell donor, which lacked the FV defect.
authors.affiliation: Department of Laboratory Medicine, University of Washington, Seattle 98195, USA.
authors.forename: K P
authors.initials: KP
authors.lastname: Crookston
authors.forename: R
authors.initials: R
authors.lastname: Henderson
authors.forename: W L
authors.initials: WL
authors.lastname: Chandler
mesh_terms: D001796:Blood Protein Disorders / Q000175:diagnosis*; D004247:DNA / Q000032:analysis; D005165:Factor V / Q000235:genetics*; D005188:False Negative Reactions; D005260:Female; D005821:Genetic Techniques / Q000592:standards; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007951:Leukemia, Myeloid / Q000628:therapy; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction; D011486:Protein C; D013927:Thrombosis / Q000235:genetics*
chemical_list: D011486:Protein C; C095381:factor V Leiden; D005165:Factor V; D004247:DNA