Hidden errors are those that cannot be detected or corrected by the laboratory analyst prior to testing. Most often these errors can be prevented by the phlebotomist following correct venipuncture procedure for every procedure, every time.
Hidden errors include hemoconcentration, incorrect order of draw, and (the most serious of all errors) misidentification of patient or specimens (Table 5). Because these errors often are unknown, the analyst may inadvertently report erroneous patient results which could be harmful to the safety and well-being of the patient.
Table 5. Examples of Hidden Errors and their Effects.| Condition | What is it? | How does it happen? | What is the Result? |
| Hemoconcentration | Blood pools at site of venipuncture | Tourniquet is applied for a prolonged period of time | Test results may be inaccurate because blood components move between blood and tissues |
| Pouring Blood between tubes | Mixing contents of two or more tubes | Removing top of tube to combine contents of one tube with another | - Inaccurate test results due to over or under dilution or incorrect anticoagulant
- Clots form due to lack of mixing
- Patient may have to be redrawn
|
| Incorrect patient identification and incorrect specimen labeling | Using the wrong name to label a specimen | - Failure to positively identify EVERY patient using 2 unique identifiers BEFORE beginning venipuncture
- Failure to reconfirm EVERY labeled tube with patient or wrist band
- Failure to concentrate fully on the task
| - Results reported to caregiver for wrong patient
- Compromises patient care; may be life-threatening
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