Introduction:Serum blood collection tubes with separator gel are widely used by many laboratories for chemistry analyses. We describe a case of a primary blood collection tube filled with blood sample and a floating separator gel.Materials and methods:The blood sample was collected from a 51 years old female in intensive care unit with the diagnosis of pneumonia into a BD Vacutainer SST tube (Becton Dickinson, NJ, USA) containing serum separator gel and conveyed to the core laboratory of Marmara University Hospital within 30 minutes from collection. Sample was immediately centrifuged at room temperature at 1500 × g for 10 minutes.Results:The analyses revealed a highly increased total protein concentration of 145 g/L (reference interval 64–83 g/L). The nephelometric analyses showed an elevated serum IgG concentration of 108 g/L (reference interval 6.5–16 g/L) and IgG lambda monoclonal band was determined by serum immunofixation electrophoresis.Conclusion:Limitation of the separator gel tubes in patients with a high plasma density and its possible effects on test results and laboratory costs should be remembered. The clinical diagnosis stated in the information system should also reveal known comorbid conditions besides the apparent admission reason. This information would avoid resampling, additional testing, and communication efforts with the clinicians.

Objective Homocysteine is a sulfur containing amino acid that is formed during methionine metabolism. Patients under long-term antiepileptic drug treatment often have hyperhomocysteinemia. These patients have low levels of serum folate, vitamin B12 and vitamin B6, all of which are associated with homocysteine metabolism. We have investigated the effects of valproic acid and new generation antiepileptic drugs (lamotrigine and levetiracetam) on plasma levels of homocysteine and aminothiols as well as serum vitamin B12 and folic acid. Materials and methods Forty-seven idiopathic epileptic patients on antiepileptic drugs were compared with 38 age-matched healthy controls. Commercial immunoassay methods were used for vitamin B12 and folic acid analyses. Homocysteine, cysteine, cysteinylglycine and glutathione levels were determined by high performance liquid chromatography. Results There was no significant difference in patient and control values in terms of vitamin B12, folic acid and homocysteine. Valproic acid and lamotrigine seemed to effect aminothiol redox status. Glutathione levels of epileptic patients receiving valproic acid and lamotrigine were higher than controls. Conclusion Our results suggest that redox homeostasis may be impaired and glutathione synthesis increased in response to the oxidative stress caused by antiepileptic drug use.