Main AHCA Website

AHCA’s main website for information on Medicaid, Health Quality Assurance and the Florida Center for Health Information and Transparency.

Go >

Florida Health Information Network

This website provides information and resources relating to AHCA’s initiatives for Health Information Technology and Health Information Exchange.

Go >

Provides health education and information to compare and locate health care providers in Florida to make well-informed health care decisions.

Go >
AHCA Network of Websites

Health Education

Health Encyclopedia

Search the Health Encyclopedia

Gastric culture


Gastric culture is a test to check a child's stomach contents for the bacteria that cause tuberculosis (TB).

How the Test is Performed

A flexible tube is gently placed through the child's nose and into the stomach. The child may be given a glass of water and asked to swallow while the tube is inserted. Once the tube is in the stomach, the health care provider uses a syringe to remove a sample of the stomach contents.

The tube is then gently removed through the nose. The sample is sent to a lab. There, it is placed in a special dish called a culture medium and watched for the growth of bacteria.

How to Prepare for the Test

Your child will need to fast for 8 to 10 hours before the test. This means your child cannot eat and drink anything during that time.

The sample is collected in the morning. For this reason, your child will likely be admitted to the hospital the night before the test. The tube can then be placed in the evening, and the test done first thing in the morning.

How you prepare your child for this test depends on your child's age, past experience, and level of trust. Follow your provider's instructions on how to prepare your child.

Related topics include:

How the Test will Feel

While the tube is being passed through the nose and throat, your child will feel some discomfort and may also feel like vomiting.

Why the Test is Performed

This test can help diagnose lung (pulmonary) TB in children. This method is used because children cannot cough up and spit out mucus until about age 8. They swallow the mucus, instead. (That is why young children only rarely spread TB to others.)

The test may also be done to help identify viruses, fungi, and bacteria in the gastric contents of people with cancer, AIDS, or other conditions that cause a weakened immune system.

The final results of the gastric culture test may take several weeks. Your provider will decide whether to start treatment before knowing the test results.

Normal Results

The bacteria that cause TB are not found in the stomach contents.

What Abnormal Results Mean

If the bacteria that cause TB grow from the gastric culture, TB is diagnosed. Because these bacteria grow slowly, it may take up to 6 weeks to confirm the diagnosis.

A test called a TB smear will be done first on the sample. If the results are positive, treatment may be started right away. Be aware that a negative TB smear result does not rule out tuberculosis.

This test can also be used to detect other forms of bacteria that do not cause tuberculosis.


Anytime a nasogastric tube is inserted down the throat, there is a small chance it will enter the windpipe. If this happens, your child may cough, gasp, and have trouble breathing until the tube is removed. There is also a small chance that some of the stomach contents may enter the lung.


Fitzgerald DW, Sterling TR, Haas DW. Mycobacterium tuberculosis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 251.

Hall GS, Woods GL. Medical bacteriology. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 57.

Hatzenbuehler LA, Starke JR. Tuberculosis (Mycobacterium tuberculosis). In: Kliegman RM, Stanton BF, St Geme JW III, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 215.

Review Date:8/14/2015
Reviewed By:Subodh K. Lal, MD, gastroenterologist at Gastrointestinal Specialists of Georgia, Austell, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.

Outcome Data

No data available for this condition/procedure.

Health Encyclopedia

More Features

We Appreciate Your Feedback
1. Did you find this information useful?

2. Would you recommend this website to family and friends?