White Blood Cell Differential with Microbial Identification (Qualitative)
This test examines the types of white blood cells in your blood and checks for signs of infections or other immune system responses.
["It helps identify infections, inflammation, or immune disorders by analyzing your blood cells and potential microbes."]
Key facts at a glance
- LOINC
- 13655-6
- Short code
- WBC Stl Ql Micro
- Synonyms
- WBC Stl Ql Micro
- Category
- chemistry
- Sample
- stool
- Container
- Clean container
- Units
- N/A
- Ref low
- 4.5
- Ref high
- 11
- Critical range
- 2 N/A – 30 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- microscopy-light
- CPT
- 85004
- SNOMED
- 900000000000003002
- Specimen volume
- 5 g
- Stability
- Refrigerated: 24h, Frozen: 7d
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
The test first looks at the proportions of different white blood cell types (neutrophils, lymphocytes, monocytes, eosinophils, basophils) to assess immune function and possible infections. The second part involves screening for microbial presence, such as bacteria or fungi, using a qualitative method that detects their genetic material or specific markers.
Why It Matters in Your Health
A differential white blood cell count helps doctors diagnose conditions like infections, autoimmune diseases, or blood disorders. Microbial screening supports identifying infections that may require antibiotics or other treatments.
Common Reasons for This Test
You may need this test if you have symptoms like fever, persistent fatigue, unexplained weight loss, or signs of infection (e.g., sore throat, skin rashes). Doctors also use it to monitor chronic conditions like leukemia, lupus, or immune deficiencies.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours if blood is drawn for the differential alone. Bring any medications or recent illnesses to discuss with your provider.
Reference range
Adult: 4.5-11.0 x 10^9/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
WBC Differential + Microbe Screen
Frequently asked questions
How does the test help my doctor diagnose my condition?
Can this test detect all types of infections?
What if my results show abnormal white blood cells?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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