biomedcentral.com/1471-227X/9/3/prepub Supplementary Material Additional file 1: The Consort Flowchart. The Graph provided shows the Consort flowchart of the

study. Click here for file(36K, doc) Acknowledgements Partly supported by a grant of the Swiss National Foundation. The funding source had no involvement in the study design; collection, analysis, and interpretation Inhibitors,research,lifescience,medical of the data; in the writing of the manuscript; and in the decision to submit the manuscript for publication.
The use of anion gap assessment to interpret and diagnose the etiology of metabolic acidosis was originally described by Emmet and Narins in 1977.[1] Lactic acid, a “gap” acid, is one cause of elevated Inhibitors,research,lifescience,medical anion gap metabolic acidosis,

and an elevated serum lactate level has emerged as an important tool to screen for patients in shock. Elevated serum lactate can be caused by inadequate perfusion, but may also be a product of inflammation, cytopathic hypoxia, and increased rates of glycolysis. [2-4] In critically ill patients, an elevated lactate level is indicative of increased severity of illness and subsequent serum lactate clearance predicts an improved outcome.[5,6] Rivers et al, utilized hypotension and elevated serum lactate levels to identify patients in shock and demonstrated that emergency department patients with presumed sepsis Inhibitors,research,lifescience,medical and a serum lactate level of ≥ 4.0 mmol/L and/or frank hypotension are at a significant risk of death (38–59% mortality).[7] Despite this study and multiple other investigations that document the value of measuring serum lactate concentrations, the measurement of serum lactate is still not routine.

In fact, in some institutions, serum lactate remains a “send out” Inhibitors,research,lifescience,medical test (unpublished data, Table ​Table1).1). We believe that one reason the measurement of serum lactate is not part of a standard admission battery of laboratory tests is that clinicians assume other Vemurafenib nmr commonly measured and calculated Inhibitors,research,lifescience,medical lab values, such as anion gap (AG) and base deficit (BD), accurately identify the presence or absence of hyperlactatemia. Despite previous studies showing that neither base deficit nor anion gap are effective at discriminating between the presence or absence of hyperlactatemia, [8-12] there persists the commonly TCL held belief that a normal anion gap or the absence of base deficit rules out the presence of hyperlactatemia. Table 1 Availability of serum lactate in Washington DC metro area hospitals One possible reason for this discrepancy is that hypoalbuminemia, a common finding in critically ill patients, can cause a decrease in the “normal” measured anion gap and thereby mask the presence of an elevated anion gap.[13] Therefore, some investigators have suggested that anion gap corrected for albumin (ACAG) is a more appropriate screening tool for the diagnosis of metabolic acidosis in the ICU.