Specimen Integrity and Laboratory Communication

Flashcards testing knowledge of specimen collection, preparation, centrifugation, storage, transport, chain of custody, and communication protocols based on the lecture transcript.

Why must serum be separated from red blood cells as soon as possible after clotting?

To prevent changes caused by the hemolysis of the blood cells.

What is the primary function of the central/specimen processing section in major laboratories?

The reception and preparation of specimens for analysis, including identification, logging, and categorization.

What is the most frequent cause for the rejection of chemistry specimens?

Hemolysis (the breakdown of red blood cells), followed by an inadequate volume of blood in the sample.

What is the primary reason for specimen rejection in hematology?

The clotting of the blood sample.

What are the three stages of specimen preparation involved in centrifuging?

The pre-centrifugation stage, the centrifugation stage, and the post-centrifugation stage.

Why must tube stoppers remain securely in place throughout all three stages of centrifugation?

Removing the stopper can cause a loss of carbon dioxide from the specimen and an increase in pH levels, resulting in inaccurate test results.

How long does complete clotting of a specimen take at room temperature?

Approximately 30 to 60 minutes.

How can a phlebotomist verify that a specimen is completely clotted?

By gently inverting the tube to check if a solid clot has formed.

Why should centrifugation not be performed more than once on a single specimen?

Repetition of centrifuging can lead to hemolysis and alter the test results.

How should a phlebotomist balance a single-tube specimen in a centrifuge?

Balance the specimen tube with a tube of the same size filled with water of the same volume as the specimen tube placed on the opposite side.

What physical signs indicate that a centrifuge is not balanced correctly during operation?

Excessive shaking, noisier operation than usual, or excessive vibrating.

What are the consequences of an overly brief versus an overly long centrifugation duration?

An excessively long time can lead to hemolysis, while a duration that is too brief may prevent proper separation of the specimen.

What is an aliquot in laboratory testing?

A specific portion of the specimen designated for testing.

According to CLSI, what is the maximum length of time serum or plasma aliquots can stay at room temperature?

No longer than 8 hours.

At what temperature range should serum or plasma be refrigerated if testing is not completed within 8 hours?

2° C to 8° C (35.6° F to 46.4° F).

At what temperature must serum or plasma be stored if it must be frozen for 48 hours?

Below -20° C (-4° F).

How must frozen samples be handled after thawing and before testing?

They must be thawed at room temperature and inverted 10 to 20 times before testing.

How long can blood specimens typically be stored and refrigerated at 2° C to 8° C without cell breakdown?

Approximately 72 hours.

What three packaging criteria do CLSI and OSHA require for specimen transport containers?

A biohazard logo, a liquid-tight closure, and a slip pocket for laboratory paperwork.

What is the CLSI recommended maximum duration threshold for a specimen to remain unprocessed during transport?

A 2-hour threshold.

At what ambient temperature are the majority of blood specimens stable for transport?

Approximately 25° C (77° F).

What temperature is maintained by portable heat blocks for body-temperature specimen transport, and for how long?

37° C (98.6° F) for around 15 minutes during transport.

What specific handling protocol is required for an ammonia level test specimen?

Immediately placed on ice or in a cooling tray, transported STAT, and processed to separate plasma from cells within 15 minutes after being drawn.

How much bilirubin is lost from a specimen after 1 hour of exposure to light?

50% of the bilirubin.

What is the purpose of an air waybill when shipping clinical research specimens?

It serves as a shipping label and tracking form containing details about the sender, recipient, and special shipping instructions.

What is the purpose of a chain of custody for forensic specimens?

To guarantee the integrity of the specimen from collection to result publication by providing documentation of the history of the specimen.

What is the difference in timing when collecting peak versus trough drug levels?

Peak levels are collected when medication concentration is at its highest, while trough levels are collected at the lowest concentration, usually right before the next scheduled dose.

In a Laboratory Information System (LIS), what does a label reading '5 mL LAV' indicate?

It indicates that a lavender tube is needed with 5 mL of blood.

What critical verification step must be performed when relaying critical values verbally over the phone?

A read-back process where the recipient repeats the information to confirm its accuracy.

Under what condition is a certified phlebotomist prohibited from performing Point-of-Care Testing (POCT)?

If the POCT is not a waived test.