Recommended minimum culture volumes are based on estimated blood volume for the patient’s weight.

The current recommendation to split volume evenly between aerobic and anaerobic culture bottles is based on best available evidence in order to maximize culture yield and minimize contaminants.

For patients >40 kg, it is recommended to obtain 2 culture sets (1 set = 1 aerobic bottle + 1 anaerobic bottle) on the first draw only. Culture sets should be obtained from 2 different sites (two peripheral or one peripheral and one central).

Follow-up blood cultures should be obtained using the same algorithm. One set is acceptable for all patient weights, unless specifically requested (e.g. checking multiple catheter lumens for clearance).

Routine blood culture is used to detect aerobic and anaerobic bacteria and yeast. The BD Blood Culture System monitors blood cultures continuously for the presence of microorganisms. When microorganisms are present they metabolize nutrients in the culture medium, releasing CO2. The bottle contains a dye in the sensor located in the bottom of the bottle which reacts with the CO2. This reaction modulates the amount of light absorbed by the fluorescent material in the sensor. A photo detector measures the level of fluorescence, which corresponds to the amount of CO2 release by the organisms and this measurement is interpreted by the system with programmed positivity parameters for carbon dioxide production by microorganisms. Positive signaling bottles are gram stained to verify positive status. The first positive set of bottles will be tested using the Verigene Blood Culture Nucleic Acid test at an additional charge. These are interim results that may be updated based on conventional culture. Verigene may not identify all the detectable organisms in the specimen, depending upon the concentration of each target present. In addition, conventional culture may be required to assign a resistance determinant to a specific pathogen. There is a risk of false negative results due to sequence variants in the bacterial targets of the assay. Conventional culture will be performed on all positive bottles at an additional charge. Test includes susceptibility testing of potentially pathogenic organism(s) at an additional charge unless specifically declined. By ordering this test the clinician acknowledges that additional reflex testing will be performed and billed at a separate additional charge if indicated.

Verigene tests for the following organisms and Resistance markers:
Gram Positive organisms: Staphylococcus species, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus lugdunensis, Streptococcus species, Streptococcus anginosus, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae, Enterococcus faecalis, Enterococcus faecium, Listeria species, mecA (methicillin), vanA (vancomycin) and vanB (vancomycin) resistance determinants.
Gram Negative organisms: Acinetobacter species, Citrobacter species, Enterobacter species, Proteus species, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa, CTX-M (ESBL), IMP (carbapenemase), KPC (carbapenemase), NDM (carbapenemase), OXA (carbapenemase), VIM (carbapenemase) resistance determinants.