Chapter 9: Specimen Processing and Pre Analytical Error

Fasting Specimens

• patient must fast for over 12 hours prior to blood draw so test results are not affected

• common for: lipid panel and glucose tests

Specimen Drawn without Stasis

• when a type of specimen is required the phlebotomist may not apply the tourniquet, even to locate the vein

• patient should not clench their fist

• common test: lactic acid

Centrifuged Specimen

• serum samples must be placed upright for 30-45 minutes to clot before placing in centrifuge

• then place in balanced centrifuge for 10-30 minutes depending on what the lab directory states

Icteric Serum

• serum appears yellow, brown, or even green

• discoloration can be caused by elevation of bilirubin levels

Lipemic Serum

• if serum appears cloudy or milky white due to high lipid levels in the blood

• cloudy appearance is called turbid and can appear if patient did not fast before blood results

Hemolyzed Serum

• tube may appear pink or reddish in color and occurs when red blood cells rupture due to errors during collection or handling

Tubes that must be centrifuged

• red top tube

• gold top (SST) tube

Chilled Specimens

• ammonia levels

• lactic acid

Light sensitive specimens

• Bilirubin

• Vitamin K

• Vitamin B12

• Vitamin B6