PHLEB CHP 9 - Specimen Processing and Pre-Analytical Errors

Laboratory Test Directory

Provides detailed specifications and requirements for most specimens collected for analysis by phlebotomists.

Such as: transport temperature, blood volume requirements, transport container, etc.

Timed Specimens

A timed specimen requires collection at a specific time of day, often to monitor a particular condition or assess the effectiveness of treatment, for accurate results.

Timing may be dependent on route of medication administration, influencing when the specimen should be collected for monitoring patient conditions, diurnal variations, medication levels, etc.

Peak levels

Reflects the highest concentration of a medication in the bloodstream.

Trough levels

Reflects the lowest concentration of a medication in the bloodstream.

STAT Specimens

Must be collected immediately (even out of normal Order-Of-Draw) after being ordered.

Possible requirements before collection

• Fasting patient specimens

  • Glucose and lipid panels

• Pre-Warmed Collection Tubes

  • Body temperature for 30 mins with warm towel or incubator.

    • Cryoglobulin test

Possible requirement during collection…

• Specimens drawn without stasis

  • No tourniquet allowed

    • Lactic acid test

Possible requirements after collection…

After collection, most samples should be kept refrigerated.

• Centrifuged specimens

  • Clot upright for 30-45 mins, then centrifuge for 10-30 mins.

  • Serum should be a clear yellow fluid after spun.

    • Red-Top tubes and Gold-Top (SST) tubes.

• Aliquoted specimens

  • After centrifuging, serum is transferred to another tube.

  • Many are frozen

    • Red-Top tubes

• Light-Sensitive specimens

  • Protected by amber tube/amber bag, or foil.

    • Billirubin test

• Warmed specimens

  • Body temperature, specimen in warming device/towel.

    • Cyrgoglobulin test

• Chilled specimens

  • Must be put on ice immediately after collection.

    • Ammonia levels

• Frozen specimens

  • Aliquoted specimens placed in a container with ice packs to freeze.

    • Hepatitis C test

Icteric Serum

Serum that is yellow, brown, green after centrifuging, caused by elevated bilirubin levels in patient’s system.

Lipemic Serum

Serum that appears cloudy (turbid) or milky white due to high lipid levels in the blood after centrifuging.

(Slightly cloudy appearance may be expected if patient did not fast prior blood draw.)

Hemolyzed Serum

Serum from a hemolyzed sample that appears pink or reddish in color after centrifuging. This is due to rupturing red blood cells during collection.

Errors before collection:

• Patient misidentification

• Improper site preparation

  • Wrong antiseptic or not clean enough

• Incorrect collection time

• Patient failure to fast

• Exercise interference

• Medication interference

• Poor coordination with other treatments

  • With IV infusions, blood transfusions, etc.

Errors during collection:

• Prolonged tourniquet time

• Improper needle size

• Insufficient blood flow

• Incorrect needle placement

• Premature needle removal

• Incorrect Order of Draw

• Incorrect collection tube

• Insufficient quantity

Errors after collection:

• Mislabeled specimen

• Failure to invert

• Vigorous mixing

• Incorrect centrifugation

  • Centrifuging before fully clotting, creating a fibrin cloth

• Failure to centrifuge

• Failure to aliquot

• Exposure to light

• Failure to maintain correct temperature