Errors encountered in some hematology tests

Question 1

WBC > 100,000/μL, large platelets, cryoglobulin, cryofibrinogen causes in RBC count

Answer 1

High RBCs

Question 2

Cause of low RBC count

Answer 2

Autoagglutination, cold agglutinins, hemolysis (in vitro), microcytosis, schistocytes, clotting

Question 3

Cause of high MCV

Answer 3

Autoagglutination, high WBC (>50,000/µL), cold agglutinins, old specimen, hyperosmolar state, reduced red cell deformability

Question 4

Cause of low MCV

Answer 4

Cryoglobulin, cryofibrinogen, giant platelets, hemolysis (in vitro), swollen red cells

Question 5

Cause of high MCH

Answer 5

Lipemia, icterus, chylomicrons, high WBC (>50,000/µL), spuriously high Hb, spuriously low RBC

Question 6

Cause of low MCH

Answer 6

Spuriously low Hb, spuriously high RBC

Question 7

Cause of high MCHC

Answer 7

Cold agglutinins, autoagglutination, clotting, hemolysis (in vitro and in vivo), spuriously high Hb, falsely low Hct

Question 8

Cause of low MCHC

Answer 8

High WBC (>50,000/µL), spuriously low Hb, spuriously high Hct

Question 9

Cause of high hemoglobin

Answer 9

Lipemia, icterus, chylomicrons, lysis-resistant RBCs, WBC > 20,000/μL, platelets > 700 x 10⁹/L, parenteral nutrition, hypergammaglobulinemia, cryoglobulin, cryofibrinogen, hemolysis (in vitro), heparin, hyperbilirubinemia

Question 10

Cause of low hemoglobin

Answer 10

Clotting

Question 11

Cause of high hematocrit (microhematocrit)

Answer 11

Dehydration, hemoconcentration, insufficient centrifugation, buffy coat inclusion, hyponatremia, plasma trapping

Question 12

Cause of low hematocrit (microhematocrit)

Answer 12

Hemolysis (in vitro), improper sealing of capillary tube, excess anticoagulant, tissue fluid contamination, hypernatremia

Question 13

Cause of high hematocrit (automated)

Answer 13

Cryoglobulin, cryofibrinogen, giant platelets, high WBC (>50,000/µL), hyperglycemia (>600 mg/dL)

Question 14

Cause of low hematocrit (automated)

Answer 14

Autoagglutination, clotting, hemolysis (in vitro), microcytic red cells

Question 15

Cause of high WBC count

Answer 15

Lysis-resistant RBCs, nucleated RBCs, megakaryocyte fragments, micromegakaryoblasts, platelet clumps, giant platelets, cryoglobulins, cryofibrinogen, heparin, monoclonal proteins

Question 16

Cause of low WBC count

Answer 16

Leukemia (with chemotherapy), leukoagglutination, clotting, smudge cells

Question 17

Cause of low neutrophils

Answer 17

Aggregation or hemosiderin granules counted as eosinophils

Question 18

Cause of high lymphocytes

Answer 18

Nucleated RBCs, giant platelets, clumps, malarial parasites, hypolobated neutrophils

Question 19

Cause of high monocytes

Answer 19

Reactive lymphocytes, lymphoblasts, lymphoma cells, immature granulocytes

Question 20

Cause of high eosinophils

Answer 20

Neutrophils with hemosiderin granules, red cells with malarial pigments

Question 21

Cause of high platelet count

Answer 21

Leukemia, fragmented RBCs (microangiopathic hemolysis), microorganisms, cryoglobulins, cryofibrinogen, hemolysis (in vitro and in vivo), microcytic RBCs, red cell inclusions, white cell fragments

Question 22

Cause of low platelet count

Answer 22

Platelet clumps, old specimen, partial clotting, giant platelets, satellitism, cold agglutinins, clotting, heparin

Question 23

Cause of high MPV

Answer 23

Old specimen, testing MPV too early in EDTA specimen

Question 24

What must be determined by the lab in consultation with users?

Answer 24

Critical values

Question 25

Who must be informed of a critical value?

Answer 25

Physician or responsible healthcare worker

Question 26

What must happen with a critical value?

Answer 26

Documented and referred to the pathologist

Question 27

When is a preliminary report issued?

Answer 27

After obtaining a critical value

Question 28

Critical hematocrit values

Answer 28

<21% or >65%

Question 29

Critical hemoglobin values

Answer 29

<70 g/L or >200 g/L

Question 30

Critical reticulocyte value

Answer 30

> 20%

Question 31

Critical WBC count values

Answer 31

<2,000/uL or >50,000/uL (new patient), 1,000 difference if <4,000/uL

Question 32

What indicates systemic infection on a blood smear?

Answer 32

Neutrophilic phagocytosis of microorganisms

Question 33

What may indicate hemolytic condition on a blood smear?

Answer 33

Schistocytes

Question 34

What abnormal forms should be noted on a blood smear?

Answer 34

Sickle cells, blast forms, intracellular organisms

Question 35

Critical platelet values

Answer 35

<20,000/uL (if not previously reported) or >1 million/uL

Question 36

Critical prothrombin time value

Answer 36

> 40 seconds