General Lab Practice Solo 2 Study Questions

An example of an unmodifiable influencing factor would be

An individual’s age

An amniotic fluid specimen for bilirubin analysis is received in the laboratory in a clear plastic collection tube. How will this affect the results of the bilirubin analysis?

Because the tube is not darkened, light will cause the bilirubin to be photo-degraded and the results will be falsely decreased

A blood collection tube containing a specific amount of additive is only half filled with blood instead of being completely filled. Will this collection affect laboratory results?

There will be a significant effect on the test results because the additive must be mixed with a full tube of blood to achieve its appropriate effect

An example of a preanalytical error would be

Mislabeling a tube of blood with an incorrect name

Why is pumping the fist before venipuncture inappropriate for blood collection?

It causes increased potassium, phosphate, and lactate

After centrifugation, plasma or serum is best separated from cells

Within two hours

Hemolysis is visible in plasma/serum at what hemoglobin concentration?

greater than 50mg/dl

What is the best way to reduce modifiable influencing factors?

Patient action and standardization

Which of the following statements is true for lipid testing and testing for lipid-soluble drugs and hormones?

Testing should always be done on the native sample before delipidation

Bilirubin absorbs light in the __ nm range

400-540

Which of the following is NOT and exogenous interference factor?

In vivo hemolysis

Which of the following cause falsely increased WBC and platelet counts?

Cold agglutination and Cryoglobulins

What are the four aspects of specimen handling?

Maintain Specimen Identification

Preservation

Separation

Transport

The most common causes of in vivo hemolysis are?

Incompatible transfusion reaction and autoimmune hemolytic anemia

Drawing from vein receiving intravenous (IV) fluid:

Increases the amount of analytes that are present in the IV fluid and dilutes the rest of the blood analytes

Which one of the following preanalytical factors should be standardized when establishing a reference interval for an analyte?

The method of specimen collection

Which one of the following is an example of an exclusion criterion when establishing a healthy population-based reference interval

Use of oral contraceptives

A physician asks your laboratory to begin performing thyroid-stimulating hormone (TSH) analysis on all specimens that have a free thyroxine (FT4) analysis ordered, a practice that your laboratory does not currently perform. Your laboratory typically performs TSH only on those FT4 specimens that are outside the population-based reference interval. The physician suggests using a subject-based reference intervals, claiming that population-based reference intervals are clinically insensitive. What is the basis of this claim?

Changes in a subject-based reference value might indicate altered biochemical status yet still be within the population-based healthy reference interval

To reduce workload in your chemistry laboratory, you are setting up a small laboratory on the opposite side of your large city from the main laboratory. When preparing the new laboratory’s chemistry analyzer, which is a larger model (but similar in all other respects) than yours. Can this be justified?

Yes, if certain conditions have been fulfilled, such as population matching, data comparison, analytical performance agreement, and specimen standardization

Visually inspecting the distribution of reference values can provide a safeguard against misinterpretation of statistical methods, and it may provide valuable information about the data. Which of the following observations might represent erroneous values?

Outlier values

The results of a certain type of quantity obtained from a single individual or a group of individuals corresponding to a stated description is the defintion of

Reference values

A subject-based reference value

Based on several samples collected over time in a single individual

When reference values are established, the criteria used to determine which individuals should be included in the group of reference individuals are referred to as

Selection criteria

In the selection of reference individuals, subclassifying a set of individuals into homogenous groups is referred to as

Partitioning

An example of a partitioning criterion is

Blood group