Salmonella and Shigella Culture (Stool) Biomarker Testing
It checks your stool for Salmonella or Shigella growth to explain infectious diarrhea, with easy ordering and Quest lab access through Vitals Vault.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
A Salmonella and Shigella culture is a stool test that looks for two common bacteria that can cause infectious diarrhea. Instead of measuring an inflammation marker or an antibody, it tries to grow (culture) the organisms from your sample so the lab can report whether they are present.
This test is most useful when your symptoms suggest a bacterial cause, when diarrhea is severe or persistent, or when you need a clear answer for treatment decisions, work/school clearance, or public health reporting.
Because many stomach bugs improve on their own, the goal is not to “test everything,” but to match the test to your situation and to interpret the result alongside your symptoms and any recent travel, food exposures, or antibiotic use.
Do I need a Salmonella and Shigella Culture test?
You may want this test if you have diarrhea that is severe, lasts more than a few days, or comes with warning signs such as fever, blood or mucus in the stool, significant belly pain, dehydration, or symptoms that are worsening instead of improving.
It can also be appropriate if you recently traveled, had a known exposure (for example, a household contact with confirmed infection), ate higher-risk foods (undercooked poultry/eggs, unpasteurized products, contaminated produce), or you work in a setting where identifying contagious infections matters (food handling, healthcare, childcare).
If you are immunocompromised, pregnant, older, or caring for a young child, clinicians often have a lower threshold to test because complications and dehydration risk can be higher.
A stool culture result supports clinician-directed care, but it does not replace a full medical evaluation, especially if you have severe dehydration, persistent high fever, or signs of sepsis.
This is a laboratory culture performed in a CLIA-certified lab; results should be interpreted with your symptoms and other tests, and they are not a standalone diagnosis of all causes of diarrhea.
Lab testing
Order labs to measure Stool Culture (Salmonella and Shigella)
from $74.67 at Quest Diagnostics
About 1 week
Schedule online — results typically within a week
Clear next steps
Guidance included, with follow-up care available
HSA / FSA
Eligible for pre-tax health spending accounts
Get this test with Vitals Vault
If you are trying to decide whether your symptoms warrant testing, Vitals Vault lets you order a Salmonella and Shigella culture and complete collection with clear instructions, then use PocketMD to understand what your result means and what follow-up questions to bring to your clinician.
This test is often ordered when you need a specific answer about contagious bacterial diarrhea. If your symptoms suggest a broader workup, PocketMD can help you map next-step options such as adding a more comprehensive stool PCR panel, checking inflammatory markers, or reviewing medication and travel history that can change interpretation.
If you have ongoing symptoms, Vitals Vault also makes it easy to reorder testing to confirm clearance when that is clinically appropriate (for example, after treatment or for return-to-work requirements), while keeping your results organized in one place for trend and documentation.
- Order online and test through a national lab network
- PocketMD helps you interpret results in plain language
- Easy reordering for follow-up testing when needed
Key benefits of Salmonella and Shigella Culture testing
- Helps confirm whether Salmonella or Shigella is the cause of your diarrhea symptoms.
- Supports treatment decisions when symptoms are severe, prolonged, or include blood or fever.
- Can guide infection-control steps at home, work, school, or childcare when contagious illness is a concern.
- Provides organism identification that can be useful when antibiotic susceptibility testing is performed.
- Helps avoid unnecessary antibiotics when the culture is negative and symptoms are improving.
- Creates documentation for clinician follow-up, clearance letters, or public health reporting when required.
- Pairs well with broader stool testing when you need a more complete explanation for persistent symptoms.
What is Salmonella and Shigella Culture?
A Salmonella and Shigella culture is a stool test that attempts to grow Salmonella species and Shigella species from your fecal sample. If the bacteria grow in the lab, the result is reported as positive (detected). If they do not grow, the result is reported as negative (not detected).
Unlike many modern “molecular” stool tests that detect bacterial DNA, a culture depends on viable organisms being present in the sample and surviving transport to the lab. That means timing, collection technique, and recent antibiotic use can affect whether the test finds the bacteria.
A positive result generally indicates you are infected with that organism and may be contagious, even if symptoms are starting to improve. A negative result does not rule out all infectious causes of diarrhea, because many other bacteria, viruses, and parasites can cause similar symptoms.
What infections can it help identify?
This culture focuses on Salmonella and Shigella, two common causes of bacterial gastroenteritis. They can cause watery diarrhea, abdominal cramps, fever, and sometimes bloody stools. Shigella is particularly associated with dysentery-like illness and can spread easily person-to-person.
How it differs from a stool PCR panel
A stool PCR panel (also called a gastrointestinal pathogen panel) can detect many organisms at once and may be more sensitive, especially if the bacteria are present in low amounts. A culture is narrower, but it can provide an isolate that may be used for susceptibility testing and public health tracking in some settings.
Why your clinician may still order other tests
If your symptoms persist, you may need evaluation for dehydration, electrolyte imbalance, inflammatory bowel disease, medication side effects, or noninfectious causes. Depending on your story, follow-up testing can include ova and parasite exams, C. difficile testing (especially after antibiotics), fecal calprotectin/lactoferrin, or blood work.
What do my Salmonella and Shigella Culture results mean?
Negative (not detected) result
A negative culture means Salmonella and Shigella did not grow from your stool sample. If your symptoms are improving, this often supports supportive care such as hydration and diet adjustments. If symptoms are severe or persistent, a negative culture does not rule out other infections (like Campylobacter, STEC/E. coli, viruses, parasites, or C. difficile) or noninfectious causes, so your next step may be broader stool testing or a clinician evaluation.
Expected (no growth of Salmonella/Shigella)
For most people, the expected result is no growth of Salmonella or Shigella. When your result matches this expectation, interpretation depends on how you feel: mild, self-limited diarrhea can still be viral or food-related irritation. If you have red-flag symptoms, your clinician may look for other pathogens or consider dehydration labs and inflammatory markers to guide care.
Positive (detected) result
A positive culture means the lab grew Salmonella or Shigella from your sample, which strongly supports an active infection and potential contagiousness. Treatment varies by organism, symptom severity, and your risk factors; some cases improve without antibiotics, while others benefit from targeted therapy. You may also be advised on isolation, hand hygiene, and return-to-work/school timing, and in some cases the lab may perform or reflex to antibiotic susceptibility testing.
Factors that influence your result
Recent antibiotics can reduce bacterial growth and lead to a false-negative culture. Delays in getting the sample to the lab, improper storage, or using the wrong collection container can also lower detection. Early infection, intermittent shedding, and watery stools can affect how much organism is present in the sample. If your symptoms strongly suggest bacterial dysentery but the culture is negative, a stool PCR panel or repeat testing may be discussed with your clinician.
What’s included
- Salmonella And Shigella, Culture
Similar tests to consider
Frequently Asked Questions
Do I need to fast for a Salmonella and Shigella stool culture?
No. Fasting is not required because the test uses a stool sample, not blood. The most important step is collecting the sample correctly and getting it to the lab promptly using the provided container and instructions.
How long does a Salmonella and Shigella culture take?
Many stool cultures take a few days because the lab needs time to grow organisms and confirm identification. Your exact turnaround time can vary by lab workflow and whether additional identification or susceptibility testing is needed.
What does “no Salmonella or Shigella isolated” mean?
It means the culture did not grow Salmonella or Shigella from your sample. It does not rule out other causes of diarrhea, including other bacteria, viruses, parasites, or noninfectious conditions, so persistent or severe symptoms still deserve follow-up.
Can antibiotics affect my stool culture result?
Yes. Antibiotics taken before collection can suppress bacterial growth and increase the chance of a false-negative result. If you already started antibiotics, tell your clinician and consider whether a molecular stool test or repeat testing is more appropriate.
Is a stool culture the same as a GI PCR panel?
No. A culture tries to grow specific bacteria, while a GI PCR panel detects genetic material from many pathogens at once. PCR panels are broader and often faster, while cultures can be useful for organism isolation and susceptibility testing in certain cases.
When should I retest after a positive Salmonella or Shigella result?
Retesting depends on why you are testing. Many people do not need a “test of cure” if symptoms resolve, but some jobs, childcare situations, or public health guidance may require clearance testing. Your clinician can advise on timing because shedding can continue after you feel better.