Routine Hematology Tests Flashcards
control samples are run to assure the reliability of test results and can detect:
a. pre-analytical errors. b. wrong patient ID c. analytical errors. d. a partially clotted EDTA sample.
c. analytical errors
What are some sources of error when it comes to blood collection?
wrong patient ID, partially clotted blood, hemolysis, hemodilution, hemoconcentration, wrong tube or insufficient fill.
what is included in a CBC?
WBC, PLT, RBC and all the RBC components= hemoglobin, hematocrit, MCV, MCH, MCHC, RDW%
how can you approximate the HgB and HCT from the RBC count?
rbc count x 3= hgb
hgb x 3= hct
(approximate)
what is normal white count? normal HgB? normal PLT?
wbc = 4-11k/uL HgB= 12-17g/dL PLT= >150k/uL
what is leukopenia? what is leukocytosis?
decreased wbc and increased wbc, respetively.
What is Hgb? how is hemoglobin measured?
it tells us the amount of 02 being carried in the cells. it is measured photometrically. it is NOT the same as a Hgb test
what is hematocrit?
percentage of red cells in a known volume of whole blood.
what three tests parallel each other?
rbc, hgb, and hct. decrease and increase together.
who has the highest hgb counts (men, women, newborns or children?)
newborns. then followed by men, children, and females.
what does a decreased RBC, hgb, and hct mean?
anemia
increased RBCs, HGB, and HCT means what?
polycythemia, due to increased production or fluid loss.
What are RBC indices?
they define the size and or/hgb content of the red cells and include: MCV: mean cell volume MCH: mean cell hemoglobin MCHC: mean cell hemoglobin concentration RDW: red cell destribution width
What does MCV tell you?
it is hte avg. RBC size, and it varies with age. normal range for adults is 82-98 = normocytic. (newborn MCV= 110, children = 77)
MCV< 82 = microcytic
MCV > 98 = macrocytic
What is MCH?
it varies with RBC size and Hgb content. Generally parallels changes in MCV
What is the MCHC?
average hgb concentration per RBC. normal is around 30%. less than 30 indicates that cells may by hypochromic.
what is the RDW?
index of RBC size and variation. you want it be low (around 10-14)%)–> this means all RBCs are about the same size. If it is high then you will expect variation in RBC size (called anisocytosis on report).
what is anisocytosis?
high rdw (RBCs are varying in size)
what is a signifcant RDW value?
> 22
You should always compare the MCV value to what other value
RDW, because RDW can be elevated which throws off the other diagnositcs.
what is the reference range for platelets?
150-450 thousand. decreased PLT count = thrombocytopenia (decrased production or increased desctruction). increased PLT = thromcytosis (increased production, post splenectomy). CRTICAL VALUES = LESS THAN 40,000 OR GREATER THAN 1 MILLION
What must be done for all critical PLT counts/
they must be verified by microscopic exam. A major source of error is platelet clumping.
What two types of differentials are there?
automated and manual. Manual should be done truly sick patients because it can also tell you morphology (as well as several other things, look at powerpoint slides)
What is more reliable in the differential…the absolute number or the %?
the absolute number
What is the number one cell type morphology in adults? children?
adults = neutrophils
children - lymph
What cell type is ALWAYS abnormal?
-blasts.
What is the reticulocyte count?
measures the rate of RBC production by the bone marrow. Retics appears as polychromasia on a Wright’s stained blood smear. must ORDER a retic count.
What is the decreased retic count called? what about increased?
decreased = reticulocytopenia (decreased RBC production) increased = reticulocytosis. (EPO stimulus, good indicator for hemolytic anemia!!)
What is the ESR or sed rate?
it is a non-specific indicator or of disease. It is used to monitor patietns with chronic inflammatory disease process. ESR refers to the rate red cells settle as blood stands in a tube. in a normal person, sedimentation is SLOW. reported as distance the red cells fall in mm/time.
ESR varies by…
age and sex. ESR gets faster as we get older.
What is rouleaux?
under normal conditions, red cells do not form rouleaux (stacks of RBCs). High concentrations of certain plasma proteins promote rouleaux which increases ESR. Ex. fibrinogen.
What acute phase reactant is responsible for an increased ESR
fibrinogen
What is the significance of increased or abnormal ESR rates?
acute or chronic bacterial infections
chronic inflammatory diseases such as RA or SLE
malignances, tissue necrosis, MI, anemia, chronic disease.
