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Streptococcus species identification (serum/plasma culture or direct detection)

Published: August 9, 2026Updated: August 16, 2026

This test helps identify which type of Streptococcus bacteria may be present in your blood or serum/plasma, often used to guide treatment for infections like bacteremia or endocarditis.

Quick summary

["Determines the bacterial strain causing potential blood infections for targeted antibiotic treatment."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
103601-1
Short code
S. aureus MLVA type Islt/Spm
Synonyms
S. aureus MLVA type Islt/Spm
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

How the Test Works

The test may involve culturing blood or serum/plasma samples to grow Streptococcus bacteria, or using molecular methods (like immunoassay) to detect specific bacterial markers. Results help pinpoint the exact species, which informs antibiotic choices.

Why It’s Done

Doctors order this test if you have symptoms like fever, chills, or signs of infection (e.g., heart valve issues, skin sores) that may suggest a Streptococcus infection. It’s also used in monitoring patients with known risks, such as those with heart conditions or weakened immune systems.

Sample Collection

A blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab where it may be cultured or tested directly for Streptococcus species. Avoid alcohol-based hand sanitizers before drawing blood to reduce contamination risk.

Preparation

No special preparation is needed, but inform your doctor about any medications (especially antibiotics) or recent infections you’ve had. Some tests may require fasting, but this is rare for this type of test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Strep Grouping Test

Frequently asked questions

What does a positive result mean?
A positive result confirms the presence of Streptococcus bacteria in your sample. The exact species identified will guide your doctor’s antibiotic choice. Always follow their instructions for further testing or treatment.
How long will I need to wait for results?
Results may take 24–72 hours for culture-based tests or less for direct detection methods. Your doctor will discuss the findings with you during your follow-up visit.
Can I take antibiotics before the test?
No, antibiotics can alter test results. If you’ve already taken antibiotics, inform your doctor immediately—they may need to adjust the test approach or timing.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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