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Respiratory Microbial Profile (Lower Respiratory Tract) - Culture and Sensitivity

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

This test helps identify bacteria or other microbes in your lower respiratory tract, such as those found in sputum or bronchial secretions, and determines how they may respond to antibiotics.

Quick summary

["It supports diagnosing infections like pneumonia and guides treatment choices."]

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

Key facts at a glance

LOINC
91826-8
Short code
O+P Lower resp Micro
Synonyms
O+P Lower resp Micro
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
microscopy-light
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

What This Test Measures

The test detects the presence of microorganisms (such as bacteria, fungi, or viruses) in your respiratory tract. It also evaluates their sensitivity to various antibiotics, helping healthcare providers choose the most effective treatment.

Why It’s Ordered

Your doctor may recommend this test if you have symptoms like persistent cough, fever, chest pain, or difficulty breathing, especially if other tests (like a chest X-ray or bloodwork) suggest an infection.

Sample Collection and Preparation

A sterile sample of respiratory secretions (e.g., sputum or bronchial washings) is collected. The sample is then cultured in controlled environments to grow and identify microbes, followed by testing for antibiotic resistance.

Common Findings and Their Implications

Positive results may reveal specific bacteria (e.g., *Staphylococcus aureus*, *Pseudomonas aeruginosa*) or fungi, which can guide targeted antibiotic therapy. Negative results mean no obvious microbes were detected in this sample.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lower Resp Microbial

Frequently asked questions

How long does it take to get results from this test?
Results typically take 3–7 days, depending on the lab’s processing speed and the complexity of microbial identification. Some rapid methods may provide preliminary results sooner, but full sensitivity testing often requires longer.
Can I take antibiotics before getting this test?
Yes, but it’s best to avoid antibiotics unless prescribed by your doctor, as they may alter the microbial culture results. If you’ve already taken antibiotics, inform your healthcare provider so they can interpret the results accurately.
Is there any preparation needed before this test?
No special preparation is usually required, but avoid smoking or inhaling irritants (like cigarette smoke) for 24 hours before the test, as they may affect sample quality.
  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