This is an prospective observational study assessing the effect of vitamin B12 on the odds of developing sepsis in patients with infection confirmed by a positive culture result.

The hypothesis is that patients with infection confirmed by positive cultures who develop sepsis have lower vitamin B12 levels than patients infection, confirmed by positive cultures, who do not develop sepsis.

Inclusion Criteria:

• Adults (≥18 years old)
• Infection, confirmed by a positive culture result
• Signed informed consent.

Exclusion Criteria:

• Pregnancy and/or breast feeding
• Inability to follow the procedures of the study, due to language problems, psychological disorders, social conditions or dementia

Patients who present to the ED with suspicion of infection, and for whom microbiological cultures are indicated,can to be enrolled into the study