Suitable procedures for transport of blood samples from general practitioners to hospital laboratories are requested. Here we explore routine testing on samples stored and transported as whole blood in lithium-heparin or serum tubes.
Blood samples were collected from 106 hospitalized patients, and analyzed on Architect c8000 or Advia Centaur XP for 35 analytes at base line, and after storage and transport of whole blood in lithium-heparin or serum tubes at 21 ± 1°C for 10 h. Bias and imprecision (representing variation from analysis and storage) were calculated from values at baseline and after storage, and differences tested by paired t-tests. Results were compared to goals set by the laboratory.
We observed no statistically significant bias and results within the goal for imprecision between baseline samples and 10-h samples for albumin, alkaline phosphatase, antitrypsin, bilirubin, creatinine, free triiodothyronine, γ-glutamyl transferase, haptoglobin, immunoglobulin G, lactate dehydrogenase, prostate specific antigen, total carbon dioxide, and urea. Alanine aminotransferase, amylase, C-reactive protein, calcium, cholesterol, creatine kinase, ferritin, free thyroxine, immunoglobulin A, immunoglobulin M, orosomucoid, sodium, transferrin, and triglycerides met goals for imprecision, though they showed a minor, but statistically significant bias in results after storage. Cobalamin, folate, HDL-cholesterol, iron, phosphate, potassium, thyroid stimulating hormone and urate warranted concern, but only folate and phosphate showed deviations of clinical importance.
We conclude that whole blood in lithium-heparin or serum tubes stored for 10 h at 21 ± 1°C, may be used for routine analysis without restrictions for all investigated analytes but folate and phosphate.