1.
Causes of spurious decrease in MCV.
Correct Answer(s)
A. Cryoglobulin
B. Cryofibrinogen
E. >50,000/uL WBC
Explanation
The presence of cryoglobulin and cryofibrinogen can cause a spurious decrease in mean corpuscular volume (MCV). Cryoglobulins are proteins that can precipitate and form clumps in cold temperatures, which can interfere with the measurement of MCV. Cryofibrinogen is a protein that can also form clumps in cold temperatures and affect MCV measurements. Additionally, a high white blood cell count (>50,000/uL WBC) can lead to a spurious decrease in MCV. Swollen red cells and hyperglycemia are not directly related to causing a spurious decrease in MCV.
2.
Causes of spurious decrease in microhematocrit.
Correct Answer(s)
B. Excess EDTA
C. Hemolysis
E. Hypernatremia
Explanation
Excess EDTA, hemolysis, and hypernatremia can all cause a spurious decrease in microhematocrit. Excess EDTA, an anticoagulant, can lead to inaccurate results by causing clumping of red blood cells, which affects the separation of plasma and red blood cells. Hemolysis, the breakdown of red blood cells, can also lead to a false decrease in microhematocrit as it releases hemoglobin into the plasma, altering the ratio of red blood cells to plasma. Hypernatremia, an elevated level of sodium in the blood, can cause shrinkage of red blood cells, leading to a lower microhematocrit value.
3.
Causes of spurious increase in automated Hct.
Correct Answer(s)
A. Hyperglycemia
B. Cryoglobulin
C. Cryofibrinogen
Explanation
The spurious increase in automated Hct can be caused by hyperglycemia, cryoglobulin, and cryofibrinogen. Hyperglycemia refers to high blood sugar levels, which can affect the accuracy of the automated Hct measurement. Cryoglobulin and cryofibrinogen are abnormal proteins that can cause blood to clot, leading to an incorrect Hct reading. These factors should be taken into consideration when interpreting automated Hct results to ensure accurate diagnosis and treatment.
4.
Causes of spurious decrease in automated Hct.
Correct Answer(s)
B. Autoagglutination
C. Clotting
E. Microcytic red blood cells
Explanation
Autoagglutination, clotting, and microcytic red blood cells can all cause a spurious decrease in automated Hct. Autoagglutination refers to the clumping of red blood cells, which can interfere with the accurate measurement of Hct. Clotting can also lead to inaccurate results by causing the formation of clots that may trap red blood cells. Microcytic red blood cells, which are smaller than normal, can cause a decrease in Hct values as they occupy less volume in the blood sample. These factors can all contribute to a false decrease in the automated Hct measurement.
5.
Causes of spurious increase in platelet count.
Correct Answer(s)
A. Hemolysis in vivo and in vitro
C. Microcytic red blood cells
Explanation
Hemolysis in vivo and in vitro refers to the breakdown of red blood cells, which can release platelets into the bloodstream and cause a spurious increase in platelet count. Microcytic red blood cells, which are smaller in size, can also lead to an increase in platelet count due to their abnormal interaction with platelets. This can occur in conditions such as iron deficiency anemia. The other options, clotting, giant platelets, and heparin, do not directly cause a spurious increase in platelet count.
6.
Causes of spurious decrease in platelet count.
Correct Answer(s)
A. Platelet clumping
B. Platelet satellitosis
C. Giant platelets
D. Heparin use
E. Clotting
Explanation
Platelet clumping, platelet satellitosis, giant platelets, heparin use, and clotting are all potential causes of a spurious decrease in platelet count. Platelet clumping refers to the aggregation of platelets, which can falsely lower the count. Platelet satellitosis occurs when platelets adhere to neutrophils, leading to a decrease in the apparent platelet count. Giant platelets are larger than normal platelets and can be mistakenly counted as multiple platelets, resulting in a lower count. Heparin, a blood thinner, can cause platelet clumping and falsely decrease the count. Clotting in the blood sample can also lead to a lower platelet count.
7.
Causes of spurious decrease in RBC ct
Correct Answer(s)
B. Autoagglutination
C. Clotting
Explanation
Only hemolysis in vitro and not in vivo could cause a spurious decrease in RBC ct.
8.
Causes spurious increase in Hb:
Correct Answer(s)
A. Carbohyhemoglobin (>10%)
B. Hemolysis in vitro
C. Lipemia
D. Hyperbilirubinemia
Explanation
The presence of carbohyhemoglobin (>10%), hemolysis in vitro, lipemia, and hyperbilirubinemia can cause a spurious increase in Hb levels. Carbohyhemoglobin is formed when carbon monoxide binds to hemoglobin, leading to an increase in Hb levels. Hemolysis in vitro refers to the breakdown of red blood cells outside of the body, which can release additional Hb into the sample and cause an increase in Hb levels. Lipemia, the presence of excessive fat in the blood, can interfere with the measurement of Hb levels and give a falsely high result. Hyperbilirubinemia, an excess of bilirubin in the blood, can also interfere with the Hb measurement and cause an increase in Hb levels.
9.
Causes of spurious decrease in WBC ct:
Correct Answer(s)
B. Clotting
D. Smudge cells
Explanation
The presence of clotting and smudge cells can cause a spurious decrease in WBC count. Clotting refers to the formation of blood clots, which can trap and remove some of the white blood cells from the sample, leading to a lower count. Smudge cells, on the other hand, are fragile and easily broken cells that may not be counted accurately by the automated cell counters, resulting in an underestimated WBC count. Both of these factors can contribute to a falsely decreased WBC count.
10.
Causes of spurious increase in WBC ct.:
Correct Answer(s)
A. Heparin use
C. Cryoglobulin
E. Platelet clumping
Explanation
The correct answer includes heparin use, cryoglobulin, and platelet clumping as causes of a spurious increase in white blood cell count. Heparin, an anticoagulant, can cause white blood cells to aggregate, leading to an elevated count. Cryoglobulins, abnormal proteins in the blood, can also cause white blood cells to clump together, resulting in an inaccurate increase in count. Platelet clumping, where platelets stick together, can mimic white blood cells and falsely elevate the count. These factors should be considered when interpreting a high white blood cell count.
11.
Causes spurious decrease in Hb:
Correct Answer(s)
A. Clotting
C. Sulfhemoglobin
Explanation
Clotting and sulfhemoglobin are both potential causes of a spurious decrease in Hb (hemoglobin) levels. Clotting refers to the formation of blood clots, which can interfere with accurate measurements of Hb levels. Sulfhemoglobin is a form of hemoglobin that contains sulfur and cannot carry oxygen effectively, leading to a decrease in Hb levels. Therefore, both clotting and sulfhemoglobin can cause misleadingly low Hb readings.
12.
Causes of spurious increase in MCHC
Correct Answer(s)
A. Low Hct
B. High Hb
Explanation
A spurious increase in MCHC (mean corpuscular hemoglobin concentration) can be caused by a combination of low Hct (hematocrit) and high Hb (hemoglobin) levels. This can occur when there is a decrease in the volume of red blood cells (Hct) but an increase in the concentration of hemoglobin within those cells (Hb). This can lead to an artificially high MCHC value.
13.
Causes spurious increase in platelet ct:
Correct Answer(s)
B. Red blood cell inclusions
C. Hemolysis
D. Microcytic red blood cells
Explanation
Red blood cell inclusions, hemolysis, and microcytic red blood cells can all cause a spurious increase in platelet count. Red blood cell inclusions, such as Howell-Jolly bodies or Pappenheimer bodies, can be mistaken for platelets during manual counting, leading to an overestimation of the platelet count. Hemolysis, the breakdown of red blood cells, can release intracellular components that may be counted as platelets. Microcytic red blood cells, which are smaller than normal red blood cells, can be misinterpreted as platelets, resulting in an elevated platelet count.
14.
Causes spurious decrease in MCV
Correct Answer
A. Cryofibrinogen
Explanation
Cryofibrinogen can cause a spurious decrease in MCV. Cryofibrinogen is a protein that can form fibrin clots at low temperatures. These clots can trap red blood cells, leading to a false decrease in the MCV (mean corpuscular volume) measurement. This can be misleading in diagnosing certain conditions that affect red blood cell size.
15.
Causes spuriously high MCHC
Correct Answer(s)
A. Clotting
D. Autoagglutination
Explanation
Clotting and autoagglutination can cause spuriously high MCHC levels. Clotting refers to the formation of blood clots, which can lead to falsely elevated MCHC values. Autoagglutination occurs when red blood cells clump together, again resulting in falsely high MCHC levels. These two factors can interfere with accurate MCHC measurements and should be considered when interpreting results.
16.
Causes of spurious decrease in microhematocrit.
Correct Answer(s)
B. Excess EDTA
C. Hemolysis
E. Hypernatremia
Explanation
Excess EDTA, hemolysis, and hypernatremia can all cause a spurious decrease in microhematocrit. Excess EDTA, an anticoagulant, can lead to the formation of small clots in the sample, which can decrease the volume of red blood cells in the microhematocrit tube. Hemolysis, the breakdown of red blood cells, can also decrease the volume of red blood cells in the sample. Hypernatremia, an elevated level of sodium in the blood, can cause dehydration and shrinkage of red blood cells, leading to a decrease in the microhematocrit reading.