False Positive Reaction Due to Methocarbamol in the Screening Test for Vanilmandelic Acid (VMA)

False Positive Reaction Due to Methocarbamol in the Screening Test for Vanilmandelic Acid (vma).

I N PHEOCHROMOCYTOMA, 3-methoxy-4-hydroxy-rnandelic acid (VMA), a metabolite of epinephrine and norepinephrine, is excreted in urine in abnormally large quantities. Qitlow et al. (1) have developed a semi quantitative screening method for VMA that we have found to be useful and reliable. The procedure is particularly welcome because it permits screening of a large number of urines from hyperten...

Electrophoretic determination of vanilmandelic acid (VMA) in urine by direct application to cellulose acetate.

‘THE VALUE of vanilmandelic acid (3-methoxy-4-hydroxymandelic acid, 1/MA) in urine for the diagnosis of pheochromocytoma is well recognized. The comprehensive review of VMA analysis by Sunderman (1) reiterates that there is a large difference between normal and pathologic 24-hr. urinary excretion of 1/MA. Such a sharp difference in concentration makes VMA analysis adaptable to a semiquantitativ...

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,...

Ethambutol and a false-positive screening test for phaeochromocytoma.

Frequency of false positive responses in patients with multiple positive reactions in patch test

Background and aim: Contact dermatitis is an inflammatory skin response due to contact with environmental materials manifested as acute or chronic eczema. Patch test is the standard test to recognize responsible allergen. The objective of this study was to evaluate the frequency of false positive patch test responses in patients with Exited Skin Syndrome (ESS).Materials...