Date of First Infection Onset (Clinical History Review)
This test is not a laboratory blood or body fluid test but rather a review of your medical history to determine when you first became infected with a specific illness or pathogen.
Your healthcare provider uses this information to assess timing of infection for diagnosis or treatment planning.
Key facts at a glance
- LOINC
- 99350-1
- Short code
- DATEOFFIRSTINFECTIONONSET
- Synonyms
- —
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 17
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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
This is not a laboratory measurement but a documented review of your reported symptoms, test results, or clinical findings from the earliest known signs of infection. It captures the point in time when symptoms first appeared or when diagnostic confirmation was made (e.g., positive test results).
How It’s Used in Healthcare
Healthcare providers use this information to determine the duration of infection, evaluate response to treatment, or assess risk for complications. It may also help guide decisions about vaccination timing, exposure assessment, or follow-up care for infectious diseases.
Specimen and Testing Notes
No physical specimen is collected for this test. Instead, your medical records are reviewed to identify the date when infection was first documented. This may include dates from symptoms, diagnostic tests, or clinical evaluations.
Limitations and Considerations
This is a retrospective review based on your reported history and healthcare records. Accuracy depends on reliable reporting of symptoms, test results, and clinical assessments. It may not capture all possible early signs of infection if they were not documented.
Reference range
NCBI: NSE 0-17 ng/mLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Knowing the date of first infection onset helps healthcare providers tailor treatment plans, monitor progression, and assess the effectiveness of interventions. It can also inform decisions about public health reporting, vaccine timing, or exposure control measures for infectious diseases.
Frequently asked questions
Why might my healthcare provider ask for this information?
Is this test the same as a lab test?
What if I don’t remember the exact date?
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 17, 2026. · Read our editorial policy