Falsely High Plasma Potassium Values in Patients with Hyperaldosteronism

Falsely high plasma potassium values in patients with hyperaldosteronism.

The common practice of encouraging forearm exercise as an aid to venepuncture is a potent source of erroneously high plasma potassium levels. This may be sufficient to obscure a suspicion of hyperaldosteronism, with possible serious repercussions in hypertensive patients, in whom the diagnosis of hyperaldosteronism has important therapeutic implications. Plasma is preferable to serum for potass...

Falsely increased HCG in patients with high leukocyte counts.

Falsely increased plasma troponin (Tn) I and T results have been reported for several Tn methods, including the Beckman Coulter UniCel DxI AccuTnI assay (Beckman Coulter, Chaska, MN) (1–3). We and others have also observed falsely increased human chorionic gonadotropin (hCG) using the Beckman Coulter Access Total hCG on the UniCel DxI (1). These false increases were identified by the finding of...

Falsely Increased hCG in Patients with High Leukocyte Counts

Falsely increased plasma troponin (Tn) I and T results have been reported for several Tn methods, including the Beckman Coulter UniCel DxI AccuTnI assay (Beckman Coulter, Chaska, MN) (1–3). We and others have also observed falsely increased human chorionic gonadotropin (hCG) using the Beckman Coulter Access Total hCG on the UniCel DxI (1). These false increases were identified by the finding of...

Falsely normal values of intact parathyrin in serum of patients with mild primary hyperparathyroidism?

Falsely elevated prothrombin international normalized ratio values.

International normalized ratio (INR) monitoring is essential during oral anticoagulation therapy to minimize bleeding complications and thrombotic events. Laboratory technicians cannot differentiate falsely elevated INR results due to problems in drawing blood from truly elevated INR values, but the extent of this phenomenon is unclear. We determined the proportion of patients with INR values o...