Laboratory Testing: What This Test Is and What to Expect

What is this test? This laboratory test analyzes a sample from your body, most often blood, to measure specific substances and cells. It helps your doctor check your overall health, screen for medical conditions, or monitor how a treatment is working.

The Bone Marrow Culture test is a diagnostic laboratory procedure that detects and identifies bacteria present in bone marrow. Bone marrow is the spongy tissue inside bones where blood cells are produced. This test uses two culture methods: aerobic culture (for bacteria that need oxygen) and anaerobic culture (for bacteria that grow without oxygen). The sample is collected by a procedure called bone marrow aspiration or biopsy, where a small amount of liquid bone marrow is drawn out using a special needle.

How is the sample collected? A trained healthcare professional will usually draw a small amount of blood from a vein in your arm using a sterile needle. Depending on the test ordered, you may instead be asked to provide a urine, saliva, or swab sample.

A healthcare provider collects the bone marrow sample, usually from the hip bone (iliac crest) or breastbone (sternum). The area is numbed with local anesthesia, and a thin needle is inserted to withdraw liquid bone marrow. Although the test information indicates serum as the sample type, bone marrow culture actually requires bone marrow fluid (not blood serum) for accurate bacterial detection. The collected sample is then placed in special culture containers and sent to the laboratory for analysis.

What happens in the laboratory? Your sample is carefully labeled and sent to a certified laboratory, where trained technicians examine it using specialized instruments and chemical analyses to measure the components your doctor needs to evaluate your condition.

In the laboratory, the bone marrow sample is divided and placed in different culture media. One portion is incubated in oxygen-rich conditions (aerobic culture) to grow bacteria that require oxygen. Another portion is incubated in oxygen-free conditions (anaerobic culture) to grow bacteria that thrive without oxygen. Laboratory technicians monitor the cultures over several days to see if bacteria grow. If bacteria are detected, further testing is done to identify the exact type of bacteria and determine which antibiotics will be most effective.

How long does it take to get results? Most routine laboratory results are ready within one to three days, although some specialized tests may take one to two weeks. Your doctor's office will contact you to discuss the findings and any recommended next steps.

Bone marrow culture results typically take 2 to 7 days. Some bacteria grow slowly and require longer incubation periods. If no bacteria grow after 7 days, the culture is considered negative. However, certain fastidious or slow-growing organisms may require additional time or special culture techniques for detection.