False-Positive Plasma Genotyping Due to Clonal Hematopoiesis

False-positive results of plasma PCR for cytomegalovirus DNA due to delayed sample preparation.

Positive results by cytomegalovirus (CMV) PCR of plasma are considered predictive of active CMV infection in kidney allograft recipients. To assess whether contamination with leukocyte-derived CMV DNA can distort the results, aliquots of whole-blood samples from 60 CMV immunoglobulin G-positive patients with leukocyte CMV DNAemia were stored for up to 24 h at room temperature (RT) and at 4 degr...

False-positive serum LDH level due to interference from immunoglobulin.

False-positive ODA testing results due to prescription medications .

M any over-the-counter, or OTC, medicines containing pseudoephedrine, ephedrine, or other sympathomimetic amines interfere with screening tests for amphetamines but do not cause positive test results in the gas chromatography/ mass spectrometric, or GC/MS, confirmation, thus pose no serious challenge in drugs-of-abuse (DOA) testing. In contrast, several prescription medicines containing opioid,...

False-positive Urine Pregnancy Test Due to Leukocyte Interference

Hsiu-Fen Jao, M.S., Tze-Kiong Er, Ph.D., Jen-Kuei Hsiao, M.S., and Chein-Hua Chiang, M.S. Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung; Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung,...

False-positive Aspergillus antigenemia due to blood product conditioning fluids.

The presence of Aspergillus antigens in blood transfusion components from different manufacturers was analyzed. Galacomannans were found in transfused patients, pooled platelet concentrates, fresh frozen plasma, and packed red cells collected using Fresenius Kabi bags. Galacomannans were also found in blood collection anticoagulant and platelet additive solution from this manufacturer.