The preanalytic phase of testing includes all processes prior to the actual testing of a specimen. A study that was published in 2002 concluded that 68 - 87% of laboratory errors occur in the preanalytic and postanalytic stages of the testing process with the majority occurring in the preanalytic phase.*
Steps in the preanalytic phase occur both inside and outside the laboratory, and are performed by both laboratory and non-laboratory personnel. While the following list is not exhaustive, some of the most common sources of error in the preanalytic phase include:
- Patient preparation
- Patient not told to be fasting; improper or no instruction to patient on proper collection of specimen such as clean catch urine.
- Patient injured during phlebotomy
- Development of hematoma resulting in no specimen obtained for testing.
- Requisition errors
- Patient information missing, illegible, or on wrong patient; wrong tests ordered.
- Patient identification
- Patient incorrectly identified.
- Labeling of specimen
- Specimen not labeled or incorrectly labeled.
- Preparation of specimen
- Specimen centrifuged too long or not long enough; specimen placed in improper preservative.
- Storage of specimen
- Specimen not refrigerated or frozen as required or refrigerated when it should be at ambient temperature.
- Shipment of specimen
- Shipped at ambient temperature when it should have been shipped frozen; delay in shipment.
- Accessioning process including preparation for analysis
- Sorted into wrong batch; incorrect labeling.
- Order entry
- Incorrect data entered during manual entry of a test requisition.
- Specimen sub-optimal
- Not enough specimen for testing; visible hemolysis.
- Inadequate cleansing of venipuncture site resulting in contamination during blood culture collection.
*Reference: Bonini P, Plebani M, Ceriotti F, Rubboli F. Errors in laboratory medicine. Clin Chem. 2002;48:691-698. Available at http://www.clinchem.org/content/48/5/691.full#T2B. Accessed February 16, 2016