Blood Collection Errors
that Alter Test Results

Potential Consequences to Patient

Failure to properly identify the patient

Transfusion- or medication-related death.

Patient mismanagement due to being treated according to the results of another patient.

• Failure to properly cleanse site for blood culture collection
• Repalpating a site cleansed for blood culture collection
• Failure to allow antiseptic time to take effect prior to blood culture collection.

Unnecessary administration of antibiotic & extended length of hospitalization due to false-positive blood culture.

Prolonged tourniquet application beyond one minute

• Seizure, death, & patient mismanagement due to falsely elevated potassium* level.
• Patient mismanagement due to temporary elevation of albumin, calcium, RBC count, hemoglobin, and hematocrit.
• Patient mismanagement due to temporary decrease in WBC count and differential.
• Hypovolemia, anemia, and death if hemoconcentration obscures diagnosis and condition goes untreated.

Patient allowed to pump fist

Seizure, death, patient mismanagement. Fist pumping significantly increases potassium* and ionized calcium levels in blood being drawn.

Underfilling coagulation tube

Stroke due to unwarranted decrease in blood thinner dosage necessitated by falsely prolonged coagulation times.

Underfilling EDTA tube

• Patient mismanagement/misdiagnosis from falsely decreased hematocrit and MCV.
• Unnecessary transfusion.

Underfilling heparin tube

Patient mismanagement/misdiagnosis from altered potassium, sodium, ALT, AST, amylase, and lipase results.

Underfilling blood culture bottles

Death from septicemia due to false-negative result.

Failure to properly mix tubes

Patient mismanagement due to delays when anticoagulated tubes contain clots and must be recollected.

Incorrect order of draw

• Seizure and death from potassium carrying over from EDTA into tube to be tested for K+.*
• Medication errors when additives carry over into coag tubes, falsely lengthening coagulation times and leading to unwarranted and life-threatening medication adjustments.
• Unnecessary antibiotic administration and prolonged hospitalization due to contaminated blood cultures.

• Vigorous mixing samples
• “Milking” the site of a capillary puncture
• Improper needle placement
• Pulling excessively on the plunger of a syringe
• Line draws
• Prolonged tourniquet application
• "Rimming" clot tubes during processing            

Seizure, death, medication errors, and patient mismanagement should these practices hemolyze samples causing the contents of red cells to be released into serum/plasma. Hemolysis falsely lengthens prothrombin times and elevates the reported levels of potassium,* LDH, AST, ALT, phosphorous, magnesium, and ammonia. Hemolysis falsely shortens aPTT times and decreases RBC counts, fibrinogen, and hematocrit.

Specimen drawn above IV

Death, medication errors, & patient mismanagement due to contamination by IV fluids of samples tested.

Inadequate discard volume drawn when collecting blood through vascular access device

• Stroke/hemorrhage due to modification of blood thinner dosage based on inaccurate coagulation results.
• Medication errors due to contamination.
• Patient mismanagement from altered results.

Failure to properly label the specimen

Transfusion- or medication-related death, and patient mismanagement due to being treated or transfused according to the results obtained from another patient's blood.

Failure to label the specimen at the patient’s side

Transfusion- or medication-related death, and patient mismanagement due to being treated or transfused according to the results obtained from another patient's blood.

Pouring contents of one tube into another

Patient mismanagement/misdiagnosis & medication errors based on altered results, especially potassium.* Stroke/hemorrhage due to unwarranted modification to blood thinner dosage.

Drawing timed specimens at the wrong time

Patient mismanagement/misdiagnosis & medication errors.

Delays in drawing blood cultures based on fever spike

Septicemia, death. Since fever spikes  ̴̴ 30 minutes after bacterial shedding into the bloodstream, any delay in fever-based blood culture collections limits the ability of the laboratory to grow and identify the causative organism in a timely manner.

Chilling/refrigerating samples to be tested for potassium prior to centrifugation

Seizure, death, patient mismanagement due to falsely elevated potassium level.*

• Tubes not centrifuged properly;
• Gel tubes centrifuged twice;
• Centrifuging tubes with stoppers removed.

Seizure, death, patient mismanagement due to falsely elevated potassium levels from platelets and/or red cells remaining in serum or plasma.* 

Delay in transporting/testing coagulation specimens

Stroke caused by unwarranted modification to blood thinner dosage based on inaccurate aPTT result.

Transporting sodium citrate tubes on ice

Hemorrhage, death, medication errors. Cold activation of Factor VII causes a falsely shortened prothrombin time, which may mislead the physician into increasing blood thinner dosage.

Delay in centrifuging samples to separate serum from cells

Seizure, death, patient mismanagement. Prolonged serum/cell contact causes a falsely elevated potassium level to be reported.* Other analytes affected include glucose, LD, phosphorous, creatinine, folate, vitamin B-12, ALT, AST, and ionized calcium.

Specimen not protected from light

Newborn suffers irreversible brain damage because bilirubin deterioration leads to falsely lower result, which prevents physician from ordering phototherapy.

*Patients whose reported potassium levels are falsely elevated (pseudohyperkalemia) are at risk whether their reported value is in the normal range or elevated. Actual potassium levels that are below normal (hypokalemic) but falsely elevated into the normal range by collection errors may be inappropriately cleared for surgery due to the "normalizing" of their potassium. Such patients are at risk for seizures and other complications when subjected to anesthesia. Other hypokalemic patients whose potassium levels are falsely elevated into the normal range may require rapid intervention, but go untreated. Such patients are at risk for developing cardiac arrhythmia. Patients whose potassium levels are actually normal but reported as elevated (hyperkalemic) due to collection errors may be treated for a high potassium level unnecessarily.