1.8 Hematology Problem-Solving Flashcards
A 19-year-old man came to the emergency department with severe joint pain, fatigue, cough, and fever. Review the following laboratory results:
___________________________________________________
WBCs: 21.0 x 10^9/L
RBCs: 3.23 x 10^12/L
Hgb: 9.6 g/dL
PLT: 252 x 10^9/L
Differential:
17 band neutrophils;
75 segmented neutrophils
5 lymphocytes;
2 monocytes;
1 eosinophil;
26 NRBCs
What is the correct WBC count?
A. 8.1 x 10^9/L
B. 16.7 x 10^9/L
C. 21.0 x 10^9/L
D. 80.8 x 10^9/L
B. 16.7 x 10^9/L
Corrected WBC = Total Nucleated Cell Count x [100 / (NRBC + 100)].
A manual WBC count is performed. Eighty WBCs are counted in the four large corner squares of a Neubauer hemacytometer. The dilution is 1:100. What is the total WBC count?
A. 4.0 x 10^9/L
B. 8.0 x 10^9/L
C. 20.0 x 10^9/L
D. 200.0 x 10^9/L
C. 20.0 x 10^9/L
The formula for calculating manual cell counts using a hemacytometer is:
cells counted x 10 (depth factor) x dilution factor / area counted in mm^2
or (80 x 10 x 100) / 4 = 20,000 / uL
or
20.0 x 10^9/L
A manual RBC count is performed on pleural fluid. The RBC count in the large center square of the Neubauer hemacytometer is 125, and the dilution is 1:200. What is the total RBC count?
A. 27.8 x 10^9/L
B. 62.5 x 10^9/L
C. 125.0 x 10^9/L
D. 250.0 x 10^9/L
D. 250.0 x 10^9/L
##Footnote
Regardless of the cell or fluid type, the formula for calculating manual cell counts using a hemacytometer is: # cells counted x 10 (depth factor) x dilution factor / area counted in mm^2 or
(125 x 10 x 200) / 1 = 250,000/uL
or
250.0 x 10^9/L
Review the scatterplot of WBCs shown. Which section of the scatterplot denotes the number of monocytes?
A. A
B. B
C. C
D. D
A. A
Review the following automated CBC values.
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WBC = 17.5 x 10^9/L (flagged)
RBC = 2.89 x 10^12/L
Hgb = 8.1 g/dL
Hct = 25.2%
MCV = 86.8 fL
MCH = 28.0 pg
MCHC = 32.3%
PLT = 217 x 10^9/L
Many sickle cells were observed on review of the peripheral blood smear. On the basis of this finding and the results provided, what automated parameter of this patient is most likely inaccurate, and what follow-up test should be done to accurately assess this parameter?
A. MCV/perform reticulocyte count
B. Hct/perform manual Hct
C. WBC/ perform manual WBC count
D. Hgb/perform serum-saline replacement
C. WBC/ perform manual WBC count
When an automated WBC count is performed using a hematology analyzer, RBCs are lysed to allow enumeration of WBCs. Sickle cells are often resistent to lysis within the limited time frame (less than 1 minute), during which the RBCs are exposed to the lysing reagent and the WBCs are subsequently counted. As a result, the nonlysed RBCs are counted along with WBCs, and this falsely increases the WBC count. When an automated cell counting analyzer indicates a review flag for the WBC count and sickle cells are noted on peripheral blood smear analysis, a manual WBC count must be performed. The manual method allows optimal time for sickle cell lysis and accurate enumeration of WBCs.
Review the following CBC results for a 2-day-old infant:
____________________________________________________
WBC = 15.2 x 10^9/L
RBC = 5.30 x 10^9/L
Hgb = 18.5 g/dL
Hct = 57.9%
MCV = 105 fL
MCH = 34.0 pg
MCHC = 33.5%
PLT = 213 x 10^9/L
These results indicate:
A. Macrocytic anemia
B. Microcytic anemia
C. Liver disease
D. Normal values for a 2-day-old infant
D. Normal values for a 2-day-old infant
##Footnote
During the first week of life, an infant has an average Hct of 55 mL/dL. This value drops to a mean of 43 mL/dL by the first month of life. The mean MCV of the first week is 108 fL; after 2 months, the average MCV is 96 fL. The mean WBC count during the first week is approximately 18 x 10^9/L, and this drops to an average of 10.8 x 10^9/L after the first month. The PLT count in newborns falls within the same normal range as in adults.
Review the following scatterplot, histograms, and automated values for a 21-year-old college student.
WBC differential:
5 band neutrophils
27 segmented neutrophils
60 atypical lymphocytes
6 monocytes
1 eosinophil
1 basophil
What is the presumptive diagnosis?
A. Infectious mononucleosis
B. Monocytosis
C. CLL
D. Beta-Thalassemia
A. Infectious mononucleosis
Review the following scatterplot, histograms, and automated values for a 61-year-old woman.
WBC differential:
14 band neutrophils
50 segmented neutrophils
7 lymphocytes
4 monocytes
10 metamyelocytes
8 myelocytes
1 promyelocyte
3 eosinophils
3 basophils
2 NRBCs/ 100 WBCS
What is the presumptive diagnosis?
A. Leukemoid reaction
B. CML
C. AML
D. Megaloblastic leukemia
B. CML
Review the automated results from the previous question. Which parameters can be released without further follow-up verification procedures?
A. WBC and relative percentages of WBC populations
B. RBCs and PLTs
C. Hgb and Hct
D. None of the automated counts can be released without follow-up verification
D. None of the automated counts can be released without follow-up verification
Refer to the following scatterplot, histograms, and automated values for a 45-year-old man. What follow-up verification procedure is indicated before these results can be released?
A. Redraw blood sample using a sodium citrate tube; multiple PLTs x 1.11
B. Dilute WBCs 1:10 multiply x 10
C. Perform plasma blank Hgb to correct for lipemia
D. Warm specimen at 37 C for 15 minutes; rerun specimen
A. Redraw blood sample using a sodium citrate tube; multiple PLTs x 1.11
The PLT clumping phenomenon is often induced in vitro by the anticoagulant EDTA. Redrawing a sample from the patient by using a sodium citrate tube usually corrects this phenomenon and allows for accurate PLT enumeration. The PLT count must be multiplied by 1.11 to adjust for the amount of sodium citrate. PLT clumps cause a spurious decrease in the PLT count by automated methods. The WBC value has an “R” (review) flag because the PLT clumps have been falsely counted as WBCs; therefore, a manual WBC count is indicated.
Refer to the following scatterplot, histograms, and automated values for a 52-year-old woman. What follow-up verification procedure is indicated before these results can be released?
A. Redraw specimen using a sodium citrate tube; multiply PLTs x 1.11
B. Dilute WBCs 1:10; multiply x 10
C. Perform plasma blank Hgb to correct for lipemia
D. Warm the specimen at 37 C for 15 minutes; rerun the specimen
D. Warm the specimen at 37 C for 15 minutes; rerun the specimen
Refer to the following scatterplot, histograms, and automated values for a 33-year-old woman. What follow-up verification procedure is indicated before these results can be released?
A. Perform a manual Hct and redraw the sample using a sodium citrate tube; multiply PLTs x 1.11
B. Dilute WBCs 1;10; multiply x 10
C. Perform plasma blank Hgb to correct for lipemia
D. Warm the specimen at 37C for 15 minutes; rerun the specimen
C. Perform plasma blank Hgb to correct for lipemia
Refer to the following scatterplot, histograms, and automated values for a 48-year-old man. What follow-up verification procedure is indicated before the five-part WBC differential results can be released?
A. Dilute WBCs 1:10; multiply x 10
B. Redraw with sample using a sodium citrate tube; multiple WBCs x 1.1
C. Prepare buffy coat peripheral blood smear, and perform a manual differential
D. Warm specimen at 37 C for 15 minutes; rerun specimen
C. Prepare buffy coat peripheral blood smear, and perform a manual differential
The markedly decrease WBC count (0.2 x 10^9/L) indicates that a manual differential is necessary and that very few leukocytes will be available for differential cell counting. To increase the yield and thereby faciliate counting, differential smears should be prepared by using the buffy coat technique.
Review the following CBC results for a 70-year-old man:
WBC = 58.2 x 10^9/L
RBC = 2.68 x 10^12/L
Hgb = 8.5 g/dL
Hct = 26.5 mL/ dL%
MCV = 98 fL
MCH = 31.7 pg
MCHC = 32.6%
PLT = 132 x 10^9/L
Differential:
96 lymphocytes
2 band neutrophils
2 segmented neutrophils
25 smudge cells/1 WBCs
What is the most likely diagnosis on the basis of these values?
A. ALL
B. CLL
C. Infectious mononucleosis
D. Myelodysplastic syndrome
B. CLL
CLL is a disease of older adults, classically assoicated with an elevated WBC count and relative and absolute lymphocytosis. CLL is twice as common in men, and smudge cells (WBCs with little or no surrounding cytoplasm) are usually present in the peripheral blood smear. CLL may occur with or without anemia or thrombocytopenia. The patient’s age and lack of blasts rule out ALL. Similarly, the patient’s age and lack of atypical lymphocytes make infectious mononucleosis unlikely. Myelodysplastic syndromes may involve the erythroid, granulocytic, or megakaryocytic cell lines but not the lymphoid cells.
Refer to the following scatterplot, histograms, and automated values for a 28-year-old woman who had undergone preoperative laboratory testing. A manual WBC differential was requested by her physician. The WBC differential was not significantly different from the automated five-part differential; however, the medical laboratory scientist noted 3+ elliptocytes/ovalocytes while reviewing the RBC morphology. What is the most likely diagnosis for this patient?
A. DIC
B. HE (ovalocytosis)
C. Cirrhosis
D. Hgb C disease
B. HE (ovalocytosis)
Refer to the following scatterplot, histograms, and automated values for a 53-year-old man who had undergone preoperative laboratory testing. What is the most likely diagnosis for this patient?
A. IDA
B. PV
C. Sideroblastic anemia
D. Beta-thalassemia minor
D. Beta-thalassemia minor
Beta-thalassemia minor can be easily detected by noting an abnormally elevated RBC count and Hct that does not correlate with the elevated RBC count, in conjunction with a decreased MCV. Although thalassemia and IDA are both microcytic, hypochromic processes, thalassemia can be differentiated from IDA because in IDA the RBC count, Hgb, and Hct values are usually decreased along with MCV. Although the RBC count is increased in PV, Hct must also be greater than 50% for diagnosis of PV to be considered.
