CH. 11 - Manual, Semiautomated, and Point-of-Care Testing

EDTA

It prevents clotting in the specimen by binding (chelating) calcium required for fibrin clot formation.

Levy chamber with improved Neubauer ruling

What is the most common hemacytometer

1:20

The typical dilution of blood for the WBC count is?

Platelets

They adhere to foreign objects and to each other, which makes them difficult to count

Manual RBC count

Rarely performed because of the inaccuracy of the count and questionable necessity

540 nm

The reference method for hemoglobin determination is based on the absorbance of cyanmethemoglobin at?

Lipemia

It can cause turbidity and a falsely high result

Carboxyhemoglobin

It takes 1 hour to convert to cyanmethemoglobin and theoretically could cause erroneous results in specimens from heavy smokers

Hematocrit (HCT)

The volume of packed RBCs that occupies a given volume of whole blood

Buffy coat

This part of the specimen should not be included in the hematocrit reading because this falsely elevates the result

Normocytic, normochromic

The Rule of Three applies only to specimens that have these types of RBCs.

Mean Cell Volume (MCV)

It is the average volume of the RBC, expressed in femtoliters (fL)

Mean Cell Hemoglobin (MCH)

It is the average weight of hemoglobin in a RBC, expressed in picograms (pg)

Mean Cell Hemoglobin Concentration (MCHC)

It is the average concentration of hemoglobin in each individual RBC. The units used are g/dL

Reticulocyte

It is the last immature RBC stage

2 days

Normally, a reticulocyte spends how many day(s) in the bone marrow?

1 day

A reticulocyte spends how many day(s) in the peripheral blood before developing into a mature RBC?

Reticulocyte count

It is used to assess the erythropoietic activity of the bone marrow

New Methylene Blue

Whole blood, anticoagulated with EDTA, is stained with a supravital stain, such as?

Reticulocyte

Any nonnucleated RBC that contains two or more particles of blue-stained granulofilamentous material after new methylene blue staining is defined as a?

Heinz bodies

They are precipitated hemoglobin that usually appear round or oval, and tend to adhere to the cell membrane

Pappenheimer bodies

They are iron in the mitochondria whose presence can be confirmed with an iron stain, such as Prussian blue

Miller Disc

It was designed to reduce the labor-intensive process of reticulocyte counting

112

A minimum of ____ cells should be counted in the small square

1000

The College of American Pathologists (CAP) hematology standard for a manual reticulocyte count is based on at least ______ red cells

Shift reticulocytes

Reticulocytes that are released from the marrow prematurely are called?

Erythrocyte sedimentation rate (ESR)

This test is ordered with other tests to detect and monitor the course of inflammatory conditions such as rheumatoid arthritis, infections, or certain malignancies.

C-reactive protein level

It may be a more predictable and reliable alternative to monitor inflammation

Rouleaux formation

It is the stacking of RBCs

Modified Westergren Method

• The most commonly used method of ESR

• It is also the method recommended by the International Council for Standardization in Hematology and the CLSI

Wintrobe Method

This method in ESR used double oxalate as anticoagulant

Point-of-care testing (POC)

• It offers the ability to produce rapid and accurate results that facilitate faster treatment, which can decrease hospital length of stay.

• It is defined as diagnostic testing at or near the site of patient care.

2.5

REVIEW QUESTION:

A 1:20 dilution of blood is made with 3% glacial acetic acid as the diluent. The four large corner squares on both sides of the hemacytometer are counted, for a total of 100 cells. What is the total WBC count (3109 /L)?

16

REVIEW QUESTION:

The total WBC count is 20 3 109 /L. Twenty-five NRBCs per 100 WBCs are observed on the peripheral blood film. What is the corrected WBC count (3109 /L)?

Cyanmethemoglobin

REVIEW QUESTION:

If potassium cyanide and potassium ferricyanide are used in the manual method for hemoglobin determination, the final product is:

Fetal hemoglobin

REVIEW QUESTION:

Which of the following would NOT interfere with the result when hemoglobin determination is performed by the cyanmethemoglobin method?

21% to 27%

REVIEW QUESTION:

A patient has a hemoglobin level of 8.0 g/dL. According to the rule of three, what is the expected range for the hematocrit?

Erythropoietic activity of the bone marrow

REVIEW QUESTION:

What does the reticulocyte count assess?

RPI

REVIEW QUESTION:

For a patient with the following test results, which measure of bone marrow red blood cell production provides the most accurate information?

Observed reticulocyte count = 5.3%

HCT = 35%

Morphology = moderate polychromasia

Inflammation

REVIEW QUESTION:

Which of the following would be associated with an elevated ESR value?

2

REVIEW QUESTION:

Given the following values, calculate the RPI:

Observed reticulocyte count = 6%

HCT = 30%