Complete Blood Count (CBC): What This Common Blood Test Measures, Why Your Doctor Orders It, and How to Understand Your Results
A laboratory test that grows and identifies bacteria from a breast milk sample to detect infections.
{"This test checks breast milk for bacterial growth","It helps diagnose breast infections like mastitis","Results guide appropriate antibiotic treatment if needed","A clean milk sample is collected from the affected breast","Results typically available in 2-5 days"}
Key facts at a glance
- LOINC
- 106042-5
- Short code
- MILKBC
- Synonyms
- Bacteria Mother Milk Cult
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, leak-proof screw-cap container (e.g., sterile urine cup or milk collection vial); transport medium acceptable for extended transport
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- female
- Age range
- 14–55 years
- Method
- culture
- CPT
- 87081
- SNOMED
- 441829004
- Specimen volume
- 5-10 mL of expressed breast milk
- Stability
- Room temperature: 2 hours; Refrigerated (2-8°C): 24 hours; Frozen (-20°C or below): 1 week. Inoculate to culture media as soon as possible, ideally within 2 hours of collection.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 48–168 hours
- Order
- routine
What is this test? A complete blood count (CBC) is a routine laboratory test that measures the cells in your blood, including red blood cells, white blood cells, and platelets, along with related values such as hemoglobin and hematocrit, giving your care team a broad picture of your overall health.
The Breast Milk Bacterial Culture test analyzes a sample of your breast milk in the laboratory to detect and identify any bacteria present. The milk is placed in special containers that allow bacteria to grow, making it possible to identify the specific type of bacteria causing any infection.
Why is this test performed? Your doctor may order a CBC as part of a routine checkup, to help diagnose symptoms such as fatigue, weakness, fever, unusual bruising, or bleeding, to monitor a known condition like anemia or infection, or to check how treatments such as chemotherapy are affecting your blood.
This test is typically ordered when a breastfeeding mother shows signs of a breast infection, such as mastitis. Symptoms may include breast pain, redness, swelling, warmth, fever, or flu-like symptoms. The test helps determine if an infection is present and what type of bacteria is causing it, which guides proper treatment.
How is the sample collected? A healthcare professional will draw a small amount of blood from a vein, usually on the inside of your elbow or the back of your hand. The site is cleaned, a needle is inserted, and the blood is collected into a tube; the procedure takes only a few minutes and may cause brief, mild discomfort.
Before expressing milk, wash your hands and clean the nipple area with sterile water or the solution provided by your healthcare provider. Express a small amount of milk into a sterile container provided by the lab. Usually, the first few drops are discarded, and the sample is taken from the middle or end of the milking session. Label the container with your name, date, and time.
What do the results mean? Your results are compared with standard reference ranges to show whether your red blood cells, white blood cells, and platelets are normal. Abnormal values can suggest anemia, infection, inflammation, clotting problems, or other conditions, and your doctor will interpret them together with your symptoms and medical history.
Results are reported as either negative (no bacteria growth) or positive (bacteria identified). Common bacteria found in breast milk include Staphylococcus aureus, Streptococcus species, and E. coli. A positive result indicates a bacterial infection, and your healthcare provider will recommend appropriate treatment, which may include antibiotics. A negative result means no significant bacteria were grown, and your symptoms may be due to non-infectious causes.
Reference range
No growth of pathogenic bacteria. Skin flora (e.g., coagulase-negative staphylococci, viridans streptococci, Corynebacterium species) may be present in low quantities as commensal organisms.N/A
Wash hands and breast with mild soap and warm water prior to collection. Express and discard the first few drops of milk to reduce contamination from skin flora. Collect midstream milk directly into a sterile, leak-proof container. Avoid touching the inside of the container or lid.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Breast milk culture is essential for diagnosing infectious mastitis, which affects up to 10% of breastfeeding women. Identifying the specific causative bacteria helps select targeted antibiotics, reducing complications like breast abscess formation. The test also helps differentiate between infectious mastitis and other conditions like blocked ducts (mastitis), ensuring appropriate management and preventing unnecessary antibiotic use.
Frequently asked questions
Do I need to stop breastfeeding if I have an infection?
How long does it take to get results?
Can bacteria in breast milk harm my baby?
What happens if my test is negative but I still have symptoms?
Sources
- 1Mayo Clinic - MastitisSource
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy