Centralized vs. decentralized blood collection: A comparison of quality indicators for the preanalytical phase.

Erik Koldberg Amundsen1,*, Solrun Fransen1, Gro Siri Birkeland Lillesund1, Tonje Versvik Larsen1, Karin Toska1

1Dept. of Medical Biochemistry, Oslo University Hospital, Oslo, Norway

Introduction: The preanalytical phase is the most common source of error in laboratory medicine. Some studies indicate that errors are more common when blood collection is performed by others than laboratory staff (decentralized). At Oslo University Hospital, Ullevål, blood collection is partly decentralized (35%).

Objectives: Investigate quality indicators for the preanalytical phase and compare the frequency of errors in samples collected decentralized to samples taken by laboratory staff (centralized).

Methods: Information about type of phlebotomist is routinely entered into the laboratory information system (LIS) for each order. Hemolytic index (HI) is determined in all serum samples with Cobas c502/c702. HI above a threshold defined for each analyte triggers an automatic comment “not analyzed due to hemolysis”. Threshold ASAT: 20. Threshold: Troponin T (TnT): 100. Samples are manually inspected and rejected for coagulation testing if tubes are filled to less than 70% for INR and APTT and less than 90% for D-dimer, Fibrinogen, Antithrombin and Anti-factor Xa. The LIS database was searched for the following text: ASAT: “not analyzed due to hemolysis”, Troponin T: “not analyzed due to hemolysis” and Coagulation analysis: “Not analyzed due to under filling” in the period 01.10.13-31.12.13. The search was limited to hospitalized patients >12 years of age. In addition, data for incorrect patient identification of samples where retrieved from the adverse event reporting system.



Quality indicator

Blood collection

p-value (chi-square)



Rejected ASAT (hemolysis)




Rejected TnT (hemolysis)




Rejected coagulation test (inadequate tube filling)




Incorrect patient ID

0,1 per 10000

7 per 10000




Table1: Error rates for centralized and decentralized blood collection.

Conclusion: Higher error rates were found with decentralized blood collection at our hospital. The findings demonstrate that education and training of the phlebotomy staff is important.

Keywords: Laboratory organization