title: A recapping system for automatic, semiautomatic, and manual use.
abstract: BACKGROUND
  Closed sample tubes are needed for stored as well as in-process samples because evaporation significantly changes analyte concentrations. In modern laboratories, it is essential that the procedures for ordering tests on stored serum samples be simple and time-efficient. Therefore, recapping and reopening of tubes should be readily possible in laboratories to save resources and time.
  
  
  OBJECTIVE
  To evaluate the recapping system MagCap, in comparison to established snap caps and unsealed tubes.
  
  
  METHODS
  Specific balls, with an iron core, fit tightly by their specific weight into openings of primary and secondary tubes as well as microtiter plates. Recapping of the tubes can be performed individually by a single dispenser or rackwise by a multidispenser. Balls can be removed individually by a pencillike magnet or rackwise. Balls can be reused after cleaning in a glassware washer or used as disposables.
  
  
  RESULTS
  Balls seal the sample tubes as effectively as snap caps and decrease evaporation significantly in comparison to unsealed tubes. Evaporation effects of up to 13% were detected in unsealed tubes (0.5 mL) within 24 hours, whereas resealing of the tubes diminished the concentration effect to less than 1%. Open samples (0.5 mL) showed a concentration effect in the refrigerator within 7 days of up to 25%. The evaporation effect of the sealed tubes was less than 3%. Multiple reopenening and recapping procedures are easily possible using magnetic forces.
  
  
  CONCLUSIONS
  The MagCap recapping system seals primary and secondary containers securely and cost-effectively with the ball cap and thus facilitates a necessary advance in sample quality.
authors.affiliation: University Hospital Greifswald, AöR, Institute of Clinical Chemistry and Laboratory Medicine, Sauerbruchstrasse, D-17487 Greifswald, Germany. matthias.nauck@uni-greifswald.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Nauck
authors.forename: Markus
authors.initials: M
authors.lastname: Nauck
authors.forename: Jochem
authors.initials: J
authors.lastname: Koetting
mesh_terms: D053000:Analytic Sample Preparation Methods; D001800:Blood Specimen Collection / Q000295:instrumentation* / Q000379:methods*; D019411:Clinical Laboratory Techniques / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D008280:Magnetics; D013048:Specimen Handling / Q000295:instrumentation / Q000379:methods