opsonic index
Very LowSpecialized Technical/Scientific (Medical, Immunological)
Definition
Meaning
A numerical measure of the capacity of blood serum to enhance phagocytosis of a specific microorganism, indicating immune response strength.
In immunology, a quantitative value, often expressed as a ratio, that compares the phagocytic activity facilitated by a patient's serum against a test organism with that of a standard or control serum. A higher index indicates greater opsonic (antibody-mediated) activity.
Linguistics
Semantic Notes
The term is strictly used within clinical and research immunology. 'Opsonin' refers to an antibody or other substance that binds to pathogens, marking them for destruction. 'Index' here denotes a calculated numerical ratio or value.
Dialectal Variation
British vs American Usage
Differences
No significant differences in usage or spelling. Pronunciation differences follow general British/American patterns.
Connotations
Purely technical with no regional connotations.
Frequency
Equally rare in both varieties, confined to specialist literature.
Vocabulary
Collocations
Grammar
Valency Patterns
The opsonic index [against/of/before/for] [pathogen] was [value].to determine/calculate/measure the opsonic index.Vocabulary
Synonyms
Neutral
Weak
Usage
Context Usage
Business
Never used.
Academic
Exclusively used in advanced biomedical, immunological, or microbiological research papers and textbooks.
Everyday
Never used.
Technical
Used in clinical laboratory reports, immunology research, and discussions of host immune response to specific pathogens.
Examples
By Part of Speech
adjective
British English
- The opsonic-index value was crucial for the diagnosis.
American English
- Opsonin-index data was collected from the samples.
Examples
By CEFR Level
- A high opsonic index means the blood serum is very effective at helping white blood cells destroy bacteria.
- The clinician ordered an opsonic index test to quantify the patient's serum's ability to opsonise the pneumococcal bacteria, suspecting a specific antibody deficiency.
Learning
Memory Aids
Mnemonic
Imagine an **OP**erator at a **SONIC** drive-in taking an **INDEX** card to measure how many burgers (pathogens) the kitchen staff (phagocytes) can eat. The number on the card is the OPSONIC INDEX.
Conceptual Metaphor
THE IMMUNE SYSTEM AS A RATING SYSTEM: The body's defense capability is quantified like a credit score or performance index.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Direct translation 'опсонический индекс' is correct but highly specialized. Avoid interpreting 'index' as 'указатель' (pointer/directory) in a general sense; here it's strictly a calculated numerical measure ('показатель', 'коэффициент').
Common Mistakes
- Confusing it with 'titre' or 'antibody titre' (the latter measures concentration, not phagocytic enhancement).
- Using it as a general term for immune strength rather than a specific, quantitative lab measure.
- Misspelling as 'opsonic indicator' or 'opsonic rate'.
Practice
Quiz
What does the 'opsonic index' specifically measure?
FAQ
Frequently Asked Questions
Its use has declined with newer, automated assays for specific antibodies and functional phagocytic tests, but it remains a historical and conceptual cornerstone in immunology.
Primarily immunologists, clinical microbiologists, infectious disease specialists, and researchers in related fields.
Yes, a value close to 1.0 (or 100% of a control serum) is often considered normal, indicating typical opsonic activity. Values significantly higher or lower indicate an enhanced or deficient immune response.
An antibody titre measures the concentration of a specific antibody in serum via dilution series. The opsonic index measures the functional consequence of those antibodies—how effectively they enhance phagocytosis—which is a more direct measure of protective immunity.