Blodkultur

Blodkultur is a microbiological test used to detect bloodstream infections by cultivating organisms from a patient’s blood. In English, the equivalent term is blood culture. The procedure helps identify the causative pathogen and determine antimicrobial susceptibility to guide treatment.

Indications for testing include suspected bacteremia or fungemia, sepsis, endocarditis, or fever in patients with immunosuppression or intravascular devices. Blood samples are drawn aseptically from venipuncture sites and placed into aerobic and anaerobic culture bottles. In adults, typical practice is to collect two to three sets totaling about 20–30 milliliters per set; in children the volume is adjusted for weight and age. Multiple sets from separate sites improve diagnostic yield and help distinguish true infection from contamination.

Cultures are processed in automated systems that monitor growth. When growth is detected, a Gram stain is performed and isolates are subcultured for identification, often using MALDI-TOF or biochemical methods. Antimicrobial susceptibility testing is performed to guide therapy. Results can be reported within 24–72 hours after collection, depending on the organism and laboratory workflow, with preliminary Gram-stain results available sooner.

Interpretation requires clinical context. Contaminants (for example, certain skin flora) may appear in a single culture, whereas true bloodstream infections typically show growth in multiple sets or persistent positivity. Factors such as prior antibiotic use and sample handling can affect yield. Blodkultur data are essential for diagnosing sepsis and bloodstream infections and for optimizing antibiotic therapy and patient outcomes.