Check whether the sample is serum or plasma
Quest's vitamin C assay prefers serum and publishes sex-specific intervals. Labcorp's assay uses plasma and lists 0.4–2.0 mg/dL. Their numbers should not be merged into a universal serum interval. Keep the laboratory, specimen and method attached to the measurement when comparing reports. [1] [2]
Notice preparation and handling
Recent intake and sample handling can influence interpretation. Vitamin C assays have specific requirements for light protection, freezing and transport. A result collected under different conditions may not be directly comparable with an earlier result, even when the units match. [1] [2]
Read concentration claims alongside pharmacokinetics
Research on vitamin C pharmacokinetics examines the relationship between oral intake, absorption and circulating concentrations. A blood concentration does not directly establish a treatment effect for a particular illness. Our source review did not establish a universal serum optimal interval attributable to Hoffer or the other foundational figures. [3] [4]
Interpret the app example as a comparison
The homepage's sample range bar makes a product concept visible. It is an illustrative interface, not a personal clinical classification. Use the original assay interval and the cited literature when deciding what a reported measurement can actually tell you. [1] [2] [3]
| Marker | Quest example | Labcorp example |
|---|---|---|
| Vitamin C | Serum: male 0.2–2.1; female 0.3–2.7 mg/dL. Assay source ↗ | Plasma: 0.4–2.0 mg/dL. Assay source ↗ |
These notes explain sources and testing context. They do not diagnose a condition, select a personal supplement dose or replace professional medical advice.