Streptococcus Group B Antigen Detection, Serum Test: Booking, Price, and Results
About Streptococcus Group B Antigen Detection, Serum Test: Booking, Price, and Results
| Field | Value |
|---|---|
| Also Known As | GBS Antigen Detection Test, Group B Strep Antigen Test, Streptococcus agalactiae Antigen Test, Group B Beta-haemolytic Streptococcus Antigen Test |
| Sample Type | Venous blood (serum); may also be performed on cerebrospinal fluid (CSF) or urine |
| Fasting Required | No fasting required |
| Report Time | Within 24 to 48 hours |
| Recommended For | Newborns with suspected GBS infection, adults with suspected invasive GBS disease, and immunocompromised individuals |
| Price | Starting at ₹1,000 |
What Is a Streptococcus Group B Antigen Detection Serum Test?
The Streptococcus Group B Antigen Detection Serum test is a laboratory test used to identify the presence of Group B Streptococcus (GBS), a type of bacteria, in body fluids such as blood, urine, or spinal fluid. It is commonly ordered for newborns showing signs of infection and for adults suspected of having invasive GBS disease. Also referred to as the GBS Antigen Detection test or Group B Strep Antigen Test, it detects a specific protein produced by GBS bacteria rather than only the bacteria.
What Does a Streptococcus Group B Antigen Detection Serum Test Measure?
This test identifies markers on the surface of GBS bacteria in a serum or body fluid sample. The following table outlines what the test detects and why it matters:
| Component | What It Detects | Why It Matters |
|---|---|---|
| GBS Antigen | A specific protein produced by Group B Streptococcus bacteria | Confirms whether active GBS infection is present in the tested body compartment |
| Streptococcus agalactiae Surface Markers | Bacterial surface antigens extracted from the sample | Enables rapid identification using latex agglutination (clumping reaction with specialised antibody-coated particles) |
This is a qualitative test, meaning results are reported as either "detected" (positive) or "not detected" (negative), rather than as a number.
Why Is a Streptococcus Group B Antigen Detection Serum Test Done?
Doctors order this test when GBS infection is suspected, particularly in newborns or individuals with weakened immune systems. The sections below explain the key reasons.
Common Symptoms That May Require This Test
The following signs may lead a doctor to request a Group B Strep (GBS) Antigen test:
- Fever in a newborn or adult
- Lethargy or unusual sluggishness, especially in newborns
- Breathing difficulties or fast breathing
- Poor feeding in infants
- Irritability or inconsolable crying in newborns
- Abnormally low body temperature in neonates
- Urinary symptoms, such as pain or frequent urination, in adults
Conditions This Test Can Help Detect
A GBS Antigen Detection test can help identify several serious conditions, including:
- Neonatal sepsis (a bloodstream infection in newborns)
- Neonatal meningitis (infection of the membranes surrounding the brain and spinal cord)
- Neonatal pneumonia (lung infection in newborns)
- Urinary tract infections caused by GBS in adults
- Skin and soft tissue infections in older or immunocompromised adults
- Invasive GBS bloodstream infections in adults with underlying health conditions such as diabetes or liver disease
Streptococcus Group B Antigen Detection Serum Test During Pregnancy
GBS is a concern during pregnancy because it can cause urinary tract infections, infection of the placenta and amniotic fluid, and infection of the uterine lining. According to the WHO, around 10 to 30% of pregnant women carry GBS in their gastrointestinal or genital tracts. While routine prenatal GBS screening at 35 to 37 weeks typically uses a vaginal-rectal swab culture, the serum antigen detection test may be used when an active GBS infection is suspected in a pregnant woman.
How to Prepare and What to Expect
No special preparation is needed for this test. Here is what you should know before your appointment.
Do You Need to Fast?
No, fasting is not required before this test. You can eat and drink normally on the day of collection. If additional tests have been ordered alongside this one, check with your doctor whether any of those require fasting.
Practical Tips Before Your Test
Keep the following in mind before your sample is collected:
- Inform your doctor about any antibiotics you are currently taking, as these may affect results.
- Drink enough water beforehand to stay hydrated, which makes blood collection easier.
- If the sample is being collected from a newborn, keep the baby as calm and comfortable as possible.
- No special dietary restrictions or clothing requirements apply for this test.
Step-by-Step Procedure
The sample collection process is straightforward and typically takes only a few minutes.
- A trained phlebotomist cleans the skin at the collection site (usually the inner arm for adults, or the heel for newborns) with an antiseptic wipe.
- A small needle is inserted into a vein to draw approximately 2 mL of blood into a sterile collection tube.
- The collected blood is processed in the laboratory to separate the serum (the clear liquid component of blood).
- The serum is mixed with a latex reagent containing GBS-specific antibodies.
- The sample is observed for agglutination, which is the visible clumping of particles that indicates a positive result.
- The processed sample is dispatched to the laboratory, and the result is reported within the turnaround time.
Factors That Can Affect Accuracy
Several factors may influence the reliability of your test result:
- Antibiotic use before sample collection, which can reduce bacterial antigen levels
- The timing of collection relative to when the infection began
- Sample handling and transport conditions
- The presence of other organisms that may cross-react with the test reagent
- Laboratory methodology used at the testing facility
Understanding Your Streptococcus Group B Antigen Detection, Serum Test Results
Your results will be reviewed by your doctor alongside your symptoms and medical history. The table below explains what each result typically means:
| Parameter | Result | Interpretation |
|---|---|---|
| GBS Antigen | Not Detected (Negative) | No GBS antigen found; suggests absence of active GBS infection in the sample tested |
| GBS Antigen | Detected (Positive) | GBS antigen present; indicates active or recent GBS infection in the body compartment tested |
Disclaimer: These ranges are general guidelines. Your doctor will interpret your results based on your age, health history, and other factors. Always consult a qualified healthcare professional for personalised medical advice.
Results During Special Conditions
Certain situations can influence how reliable this test result is.
Prior antibiotic therapy can reduce the amount of bacterial antigen in a sample, which may lead to a false-negative result even when infection is present. Research has also shown that the test's sensitivity is around 57% for blood samples, meaning a negative result does not fully rule out infection; your doctor may recommend a culture test to confirm. Additionally, adults with conditions such as diabetes, liver disease, or a weakened immune system may have altered responses that affect result interpretation.
How to Maintain Healthy Levels
The following general wellness habits are relevant for those with a history of or risk for GBS:
- Pregnant women should attend all scheduled prenatal appointments, where GBS screening is typically offered around 35 to 37 weeks.
- Practise good personal hygiene, particularly during pregnancy, to reduce the risk of bacterial spread.
- Complete any course of antibiotics prescribed by your doctor fully, even if symptoms improve early.
Lupin Diagnostics Streptococcus Group B Antigen Detection, Serum Test Price and Home Collection
The Streptococcus Group B Antigen Detection Serum test is available at Lupin Diagnostics starting from ₹1,000, with home sample collection available across cities. The table below provides approximate prices by region:
| City | Approximate Price (₹) |
|---|---|
| Mumbai | ₹1,000 |
| Bangalore | ₹1,000 |
| Chennai | ₹1,000 |
| Kolkata | ₹1,000 |
| Hyderabad | ₹1,000 |
| Pune | ₹1,000 |
Disclaimer: Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
Select the test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist, or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within the stipulated turnaround time.
Home Collection
Lupin Diagnostics offers home sample collection for the GBS Antigen Detection test across multiple cities, making it convenient for patients who are unwell or caring for a newborn. All samples are processed in NABL-accredited laboratories by experienced laboratory professionals. Your digital report is accessible via email or WhatsApp as soon as it is ready.
Frequently Asked Questions
This test detects the presence of Group B Streptococcus bacteria in body fluids such as blood, urine, or spinal fluid. It is primarily used to diagnose active GBS infection in newborns showing signs of illness, and in adults with suspected invasive GBS disease.
This test is most often ordered for newborns who show symptoms of infection shortly after birth. It may also be requested for pregnant women with signs of active GBS infection, older adults, or individuals with weakened immune systems who develop unexplained fever or other signs of bacterial illness.
Routine prenatal screening involves a vaginal-rectal swab culture performed at around 35 to 37 weeks of pregnancy, which checks for GBS colonisation rather than active infection. The Streptococcus Group B Antigen Detection Serum test is used when an active infection is already suspected, particularly in symptomatic patients.
The test has a reported sensitivity of around 57% in blood samples, which means it may not detect all cases of GBS infection. A negative result does not fully exclude infection, and your doctor may request a culture-based test to confirm the finding.
Yes, Lupin Diagnostics offers home collection for this test. A trained phlebotomist visits your home to collect the blood sample, which is then processed at an NABL-accredited laboratory. You can book through the Lupin Diagnostics website.
A positive result should be discussed with your doctor immediately so that the appropriate next steps can be taken. Do not attempt to interpret or act on the result without professional guidance, as your doctor will consider your full clinical picture before advising on further care.
Streptococcus Group B Antigen Detection, Serum Test: Booking, Price, and Results
