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Certified Histocompatibility Specialist - CHS Exam
2025 Preparation Test Bank With 230 Questions and
Correct Answers/ ASHI CHS Exam Practice Test
Peripheral whole blood contains five general cell types -
...ANSWER...✓✓ * lymphocytes (WBC)*
* monocytes (WBC)* largest white blood cell* can
differentiate into macrophages or dendritic cells
* granulocytes*
* erythrocytes*
* platelets*
FLOW: CD3 monoclonal antibody is directed against the -
...ANSWER...✓✓ CD3- antigen (T3-antigen), which is
expressed on human T lymphocytes. The monoclonal
antibody does not react with
* B-cells
* monocytes
* granulocytes
* platelets.
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FLOW: CD19 monoclonal antibody is directed against the -
...ANSWER...✓✓ CD19- antigen (B4-antigen), which is
expressed on human B lymphocytes (all stages:
precursors, pre-pre, pre, intermediate, mature)
FITC = - ...ANSWER...✓✓ Fluorescein conjugated goat
anti-human IgG (Fc-specific)
MESF = - ...ANSWER...✓✓ Molecular Equivalents of
Soluble Fluorochrome
ΔMESF = - ...ANSWER...✓✓ MESF value for test serum -
MESF value for NHS control serum
LABScreen EDTA Treatment - ...ANSWER...✓✓ * EDTA
chelates CA which precludes complement binding
* Without EDTA, complement can bind which precludes Ab
from binding
= PROZONE
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PROZONE - ...ANSWER...✓✓ false negatives or
inaccurately low results
(LABScreen = no EDTA treatment = complement binding =
block Ab binding)
Pronase - ...ANSWER...✓✓ FLOW = removes Fc receptors
or molecules bearing Fc receptor-like domains from the
surface of cells.
Irrelevant immunoglobulins may bind to Fc receptors,
their presence on the cell surface may interfere when
interpreting FLOW XM results
Fc receptors are found on - ...ANSWER...✓✓ some T-
cells, all B-cells, NK cells, and monocytes
CD3 is specific for - ...ANSWER...✓✓ T lymphocytes
CD4 is specific for - ...ANSWER...✓✓ Helper T cells
CD8 is specific for - ...ANSWER...✓✓ Cytotoxic T cells
CD19 is specific for - ...ANSWER...✓✓ B lymphocytes
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CD33 is specific for - ...ANSWER...✓✓ Myeloid cells
CD56 is specific for - ...ANSWER...✓✓ NK cells
A9 Vs A23 / A24: what are each - ...ANSWER...✓✓ A9 is
the broad antigen that was identified early on
A23 / A24 are splits of the broad antigen that were
identified later when better specificities were developed
Bw4 and Bw6 are - ...ANSWER...✓✓ public epitopes
Amino Acid Positions 80 81 82 83
Bw4 I A R L
TARL
A23, 24, 25, 32 A R L
Bw6 N L R G
LABType is - ...ANSWER...✓✓ rSSO
* Amp HLA exons with biotinylated primers
Certified Histocompatibility Specialist - CHS Exam
2025 Preparation Test Bank With 230 Questions and
Correct Answers/ ASHI CHS Exam Practice Test
Peripheral whole blood contains five general cell types -
...ANSWER...✓✓ * lymphocytes (WBC)*
* monocytes (WBC)* largest white blood cell* can
differentiate into macrophages or dendritic cells
* granulocytes*
* erythrocytes*
* platelets*
FLOW: CD3 monoclonal antibody is directed against the -
...ANSWER...✓✓ CD3- antigen (T3-antigen), which is
expressed on human T lymphocytes. The monoclonal
antibody does not react with
* B-cells
* monocytes
* granulocytes
* platelets.
,2|Page
FLOW: CD19 monoclonal antibody is directed against the -
...ANSWER...✓✓ CD19- antigen (B4-antigen), which is
expressed on human B lymphocytes (all stages:
precursors, pre-pre, pre, intermediate, mature)
FITC = - ...ANSWER...✓✓ Fluorescein conjugated goat
anti-human IgG (Fc-specific)
MESF = - ...ANSWER...✓✓ Molecular Equivalents of
Soluble Fluorochrome
ΔMESF = - ...ANSWER...✓✓ MESF value for test serum -
MESF value for NHS control serum
LABScreen EDTA Treatment - ...ANSWER...✓✓ * EDTA
chelates CA which precludes complement binding
* Without EDTA, complement can bind which precludes Ab
from binding
= PROZONE
,3|Page
PROZONE - ...ANSWER...✓✓ false negatives or
inaccurately low results
(LABScreen = no EDTA treatment = complement binding =
block Ab binding)
Pronase - ...ANSWER...✓✓ FLOW = removes Fc receptors
or molecules bearing Fc receptor-like domains from the
surface of cells.
Irrelevant immunoglobulins may bind to Fc receptors,
their presence on the cell surface may interfere when
interpreting FLOW XM results
Fc receptors are found on - ...ANSWER...✓✓ some T-
cells, all B-cells, NK cells, and monocytes
CD3 is specific for - ...ANSWER...✓✓ T lymphocytes
CD4 is specific for - ...ANSWER...✓✓ Helper T cells
CD8 is specific for - ...ANSWER...✓✓ Cytotoxic T cells
CD19 is specific for - ...ANSWER...✓✓ B lymphocytes
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CD33 is specific for - ...ANSWER...✓✓ Myeloid cells
CD56 is specific for - ...ANSWER...✓✓ NK cells
A9 Vs A23 / A24: what are each - ...ANSWER...✓✓ A9 is
the broad antigen that was identified early on
A23 / A24 are splits of the broad antigen that were
identified later when better specificities were developed
Bw4 and Bw6 are - ...ANSWER...✓✓ public epitopes
Amino Acid Positions 80 81 82 83
Bw4 I A R L
TARL
A23, 24, 25, 32 A R L
Bw6 N L R G
LABType is - ...ANSWER...✓✓ rSSO
* Amp HLA exons with biotinylated primers
