Hematology Lab testing- Indices, hematocrit
What does the red cell distribution width (RDW) indicate on the peripheral blood smear?
Variability of RBC volume
A patient has anemia with an elevated mean corpuscular volume (MCV) of 106 fL (reference range 80-100 fL). All of the following could be likely causes EXCEPT:
Vitamin B12 deficiency
If the red cell count is known, which of the following MUST also be known in order to calculate the mean corpuscular volume (MCV)?
Hematocrit
Hemoglobin (g/100mL) x 10 / RBC count (millions/mm3) is the formula for calculating:
MCH
Blood samples for complete blood counts are collected on morning rounds and stored in a rack in the phlebotomist's basket. When the phlebotomist delivers the samples to your work station, the cells and plasma in the samples have separated. One of the samples has lipemic plasma. Which of the following parameters may be affected by the lipemia?
MCHC
In patients with Sickle cell disease, upon sickling what laboratory test will see an increase?
MCHC
The hematology laboratory is experiencing instrument downtime. The laboratory has a back-up method for hemoglobin and hematocrit testing that is being used until the instrument is repaired. The hematologist calls and asks if you can provide any of the red blood cell indices. Which of the indices, if any, can you provide for the hematologist?
MCHC only
An automated complete blood count produced the following red blood cell parameters: Parameter Value Reference Interval White blood cells (WBC) 5.6 x 109/L 4.0-10.0 x 109/L Red blood cells (RBC) 3.4 x 1012/L 4.2-5.9 x 1012/L Hemoglobin 11.1 g/dL 12-16 g/dL Hematocrit 31% 37-48% MCV 92 fL 80-100 fL MCHC 38 g/dL 30-37 g/dL A specimen for a repeat complete blood count is received in the laboratory six hours later. The sample visually appears to be much lighter in color than the original sample. The technologist questions whether both samples are from the same patient. Which of the following parameter(s) is LEAST likely to change between samples, if from the same patient, and would be most useful to determine if there is a discrepancy that may be the result of a preanalytical error in sample collection?
MCV
Which of the following RBC indices is expressed in femtoliters?
MCV
Which of the following set of results would be consistent for a patient with the following findings: macrocytosis, anemia, leukopenia, and thrombocytopenia?
MCV 115 fL; Hgb 7.5 g/dL; WBC 2.5 x 103/µL; Platelets 75,000/µL
MCV is calculated using which of the following parameters?
RBC and Hct
How is the Mean Cell Volume calculated?
(Hematocrit %/ Red blood cells) X 10
The photomicrograph is a representative field from a peripheral blood smear. Which of the following MCV values correlates best with the peripheral blood picture?
105 fL
A technologist is evaluating the red blood cell morphology on a peripheral blood smear. The image on the right is a representative field from the smear. The technologist has recorded the red cell morphology as macrocytic. Which MCV value would confirm this observation?
110 fL
Calculate the mean corpuscular hemoglobin content (MCHC) when Hgb = 15 g/dL (150 g/L), RBC count = 4.50 x 106/µL (4.50 x 1012/L), and Hct = 47% (0.47).
31.9 g/dL
A complete blood count is performed on a post-surgical, post-transfusion patient. The red cell distribution width (RDW) reported with the automated cell count is 16.5%. The reference interval in this laboratory is 11.0-14.5%. What would be demonstrated on the peripheral smear that relates directly to the RDW value?
Anisocytosis
Using an automated cell counter analyzer, an increased Red Cell Distribution Width (RDW) should correlate with which of the following?
Anisocytosis
All of the following tests are included in a complete blood count (CBC), EXCEPT?
Blood culture
Which alpha thalassemia shows no anemia or evidence of disease, although a slight decrease in the MCV and MCHC may be seen?
Alpha thalassemia silent carrier
The principle behind point-of-care devices to measure hematocrit is:
Calculating the conductance of the blood sample and correcting for temperature, conductivity of the plasma, and size of the fluid segment
A two-year old male patient has the following hemogram results: Hgb = 6.7g/dLHct = 20%Platelets = 355 x 109/LRBC = 3.0 x1012/LWBC = 8.75 x 109/L Differential = 6% eos, 20% segs, 68% lymphs, 6% monos Which of the following is the MOST likely diagnosis?
Dietary iron deficiency
Laboratory results obtained on a 47-year-old patient were as follows: WBC 51.2 x 103/µLRBC 4.27 x 106/µLHGB 12.6 g/dLHCT 36.9%PLT 403 x 103/µL Differential:50% segmented neutrophils20% bands12% lymphocytes7% monocytes1% eosinophils9% metamyelocytes1% myelocytesRBC morphology: normocytic, normochromicWBC morphology: moderate toxic granulation, slight Dohle body Which test would be MOST helpful in establishing a diagnosis in this case?
Leukocyte alkaline phosphatase stain (LAP stain)
The volume percentage of red blood cells in whole blood is called:
Hematocrit
Which of the following hematology tests is used to indicate anemic conditions?
Hematocrit
Which of the following formulas will provide the value that reflects the average cell volume in a blood sample?
Hematocrit (%) x 10/RBC count (1012/L
A quick mathematical check which can be applied to verify that the hemoglobin and hematocrit values on a complete blood count correspond with each other would be
Hemoglobin X 3 = hematocrit
A 29-year-old female of Philippine descent is seen by her physician for fatigue. The patient states that a relative told her that their family has a long history of anemia.She presents with sclera icterus and her spleen is palpable. Routine blood work was initially ordered and these results were obtained: CBC ParameterPatient ResultReference IntervalsWBC6.1 X 10 9/L4.0 - 10.5 X 109/LRBC4.84 X 1012/L3.50 - 5.50 X 1012/LHemoglobin8.4 g/dL12.0 - 16.0 g/dLHematocrit28.8%36.0 - 48.0%MCV59 fL80.0 - 100.0 fLMCH17.4 pg26.0 - 34.0 pgMCHC29.3 g/dL32.0 - 36.0 g/dLRDW19.5 %11.0 - 15.0 %Platelets591 X 109/L150 - 400 X 109/L A peripheral blood smear is reviewed, revealing many codocytes (target cells) and a few schistocytes (fragmented RBCs). The majority of the RBCs that were seen in this smear were also microcytic and hypochromic. What additional laboratory tests should be performed to aid in the diagnosis of this disorder and associated anemia?
Hemoglobin electrophoresis
Which of the following analytes will be falsely decreased due to hemolysis?
Hemoglobin, Hematocrit, Red Blood Cell Count
A 5-year-old girl was brought to the emergency department with bloody diarrhea and severe abdominal pain. A complete blood count produced these results:CBC ParameterPatient ResultReference IntervalWBC9.6 x 109/L4.3 - 10.8 x 109/LHemoglobin9.1 g/dL11.5 - 13.5 g/dLHCT28%37 - 48%MCV80 fL86 - 98 fLRDW13.111 - 15Platelets90.1 x 109/L150 - 450 x 109/L The peripheral blood smear is represented in the image to the right. Which of the following condition(s) could be present in this patient when considering the information above and the cells indicated by the arrows on the peripheral smear? Please select the single b
Hemolytic uremic syndrome (HUS)
Which of the formulas given below is used to calculate MCHC- mean cell (corpuscular) hemoglobin (Hgb) concentration?
Hgb (g/dL) x 100/ Hematocrit (%)
Considering the red cell distribution width (RDW) in alpha thalassemia, how would you expect the red blood cell histogram to look?
Shifted to the left
The automated cell count reported an MCV of 75 fL for the blood specimen from which this blood smear was made. Which of the following terms best describes the cells in this field
Hypochromic/microcytic
A patient presents with fatigue. The CBC results are as seen below: ParameterValueReference IntervalWhite blood cells (WBC)5.7 x 109/L4.0-10.0 x 109/LRed blood cells (RBC)4.0 x 1012/L4.2-5.9 x 1012/LHemoglobin12.9 g/dL12-16 g/dLHematocrit34%37-48%MCV85 fL80-100 fLMCHC38 g/dL30-37 g/dL Considering all of the above information and the cells indicated by the arrows that were observed on the peripheral smear, what is the probable mechanism for the anemia that the patient is experiencing?
Increased destruction of red blood cells (RBCs) caused by an intracorpuscular abnormality
The complete blood count was obtained from a patient recently admitted to the emergency room. The red blood cell indices obtained revealed an MCV of 115 femtoliters (fL) (normal range 80 - 90 fL). The patient met the criteria for a peripheral blood smear examination. A representative field is shown on the right. All of the following conditions would be indicated by the results seen on this peripheral blood smear EXCEPT?
Iron deficiency
Calculate the red cell indices from the following set of patient data: RBC count = 5.22 x 1012/L Hemoglobin = 17.5 g/dL Hematocrit = 53%
MCV = 102 fL, MCH = 34 pg, MCHC = 33 g/dL
Calculate the red cell indices from the following set of patient data: RBC count = 3.19 x 1012/L Hemoglobin = 11.3 g/dL Hematocrit = 35%
MCV = 110 fL, MCH = 35 pg, MCHC = 32 g/dL
The image on the right is a representative field from a peripheral blood smear. What would you expect to see on the automated blood count?
MCV increased, RDW increased
A patient presents with the following measured parameters on the complete blood count: ParameterValueReference IntervalWhite blood cells (WBC)5.6 x 109/L4.0-11.0 x 109/LRed blood cells (RBC)3.6 x 1012/L4.2-5.9 x 1012/LHemoglobin9.2 g/dL12-16 g/dLHematocrit27%37-48%MCV75 fL80-100 fLRDW-CV17%11.0-15.0%
Microcytic, heterogenous anemia
An 18-year-old female has a CBC performed as part of a routine physical exam. The following results were obtained and the physician determines she is anemic. After reviewing her CBC results shown below, which of the following would be an appropriate description of the anemia? ParameterValueReference IntervalWhite blood cells (WBC)5.6 x 109/L4.0-10.0 x 109/LRed blood cells (RBC)3.7 x 1012/L4.2-5.9 x 1012/LHemoglobin9.9 g/dL12-16 g/dLHematocrit28%37-48%MCV75 fL80-100 fLRDW-CV14%11.0-15.0%
Microcytic, homogenous cell population
A patient has the following hematology test results. Classify the anemia present by choosing one of the options below. Hgb = 8.1 g/dL Hct = 31% RBC = 4.0 x 1012/L
Microcytic, hypochromic
A peripheral smear demonstrates a population of cells composed of red cells that are mostly 5 - 5.5 µm in diameter. The CBC data shows RDW of 13% (reference range 11.5-14.5%). Which of the following morphologies is consistent with these findings?
Microcytosis, low variation of cell volume
How would the RBCs appear on the peripheral blood smear if the red cell indices obtained on a patient are as follows:MCV 88.5 f1MCH 30.2 pgMCHC 33.1 %
Normocytic, normochromic
Hematocrit is:
Percentage of blood made up of red blood cells
Which of the following conditions would produce the results listed below in an anemic patient? MCV = 115 fL MCH = 30 pg MCHC = 34 %
Pernicious anemia
A technologist is evaluating a blood smear. The technologist notices variability in cell size. Which parameter from the automated complete blood count would confirm the anisocytosis observed on the blood smear?
RDW
All of the following are decreased in beta thalassemia major EXCEPT?
Red cell distribution width (RDW)
A CBC performed on a 10-year-old African-American male who was brought to the emergency department with rapid, shallow breathing and fever provided the following results: ParameterPatient ResultReference IntervalWBC28.0 x 109/L3.2- 9.8 x 109/LRBC3.88 x 1012/L4.50 - 5.70 x 1012/LHemoglobin10.0 g/dL13.6 - 17.2 g/dLMCV82 fL80 - 110 fLRDW2311 - 14.5Reticulocyte8.0%0.5 - 1.5% The image is a representative field from the peripheral blood smear. What cells are indicated by the arrows in this smear?
Sickle cells
What are the usual results of the mean corpuscular volume (MCV) and the red cell distribution width (RDW) in alpha thalassemia?
The MCV is decreased but the RDW is usually increased
An MCV is reported by the instrument as 82 fL. The MCV is flagged with a delta check alert as the previous MCV reported on this patient 12 hours earlier was 97 fL. What is a possible cause for this discrepancy?
The specimens are not from the same patient
