Figure 1. Study design and sample collection.

(A) STARD flow diagram of the cohort study. A total of 60 patients were enrolled and completed the study. For each patient, 4 separate blood draws were collected within a 6.5-hour window in a single day (mean ±SD, 3 ± 1 hour). Collections at t₁ and t₄ were split into 6 tubes to evaluate technical variability from 2 major clinical testing services (Lab 1, LabCorp; Lab 2, Quest Diagnostics). Theranos samples were collected from 2 separate retail locations at t₂ and t₃. (B) Panel of histograms showing the time between blood collections for the (top) first set of finger prick and venipuncture draws (t₂–t₁), (middle) Theranos samples (t₃–t₂), and (bottom) overall study (t₄–t₁).