The Most Common Errors in Preanalytics

The tourniquet is applied to the vein for too long and too tightly, the sample becomes haemolytic and coagulation is activated: Haemolysis interferes with many analyses in the laboratory.
Blood collection is not performed on a fasting patient: Lipaemia affects many analyses. Often the patient has not eaten breakfast, but has nonetheless not observed the full fasting period of 12 hours.
The blood is left standing until the next day or longer without the serum being separated from the clotted blood: Haemolysis, degradation and inactivation of analytes can greatly distort the results.
A stool sample is sent to the laboratory by post: Especially in the summer, this causes the range of pathogenic micro-organisms to shift completely, and sensitive germs are no longer found.
The incorrect tubes were used for the blood sample:Anticoagulant additives interfere with many analyses.
The analyte to be measured is influenced in vivo by an existing medication: The medication was not discontinued, and the laboratory receives no information about this.This produces false normal or false pathological values.
An unstable analyte requires immediate separation of the serum and transportation in a frozen state:If this is not done, both the sample and the measurement value will not be usable.
The pharmacokinetics of a drug that is to be measured is not taken into account, or the blood test is carried out at the wrong time: This gives the false impression that the medication level in the blood is poorly adjusted.
The coagulation tube is not completely filled with blood, and/or the blood is not properly mixed with the anticoagulant:This will distort the coagulation values.
The sample tube is not labelled or is incorrectly labelled:The laboratory has no possibility of checking the identity of a job or a sample, or even ensure that they are correct.
Capillaries are not completely filled when taking capillary samples:Incorrect measurement values
To top