CBC Flashcards
anticoagulant:
EDTA optimal conc
1.5mg per mL of blood
anticoagulant:
how many hours is blood valid in EDTA tube?
4 hours - room temp
24 hours - refrigerated (wbc, hct, plt)
anticoagulant of choice for platelet count
EDTA
why EDTA is preferred for platelet count?
EDTA prevents platelet aggregation
t or f. ESR should be set up within 4 hours of collection (room temp) or 6 hours (refrigerated)
false, 2 hours.
t or f. blood smear can be made from EDTA tube as long as they are made within 4 hours of blood collection.
false, 2 hours.
mean platelet volume normal range
6.8 to 10.2 fl
t or f. EDTA causes swelling of platelets (50% higher) during the first hour.
false
20% higher
insufficient EDTA
cause:
effect:
- over-filled tube
- presence of clots
EDTA color: inversions: lab section: optimal conc: action:
- lavender top
- 8 inversions
- hematology
- 1.5 mg per mL of blood
- chelation of calcium
EDTA color: inversions: lab section: optimal conc: action:
- lavender top
- 8 inversions
- hematology
- 1.5 mg per mL of blood
- chelation of calcium
CBC other name
hemogram
RBC parameters (6)
RBC ct Hgb Hct RBC indices RDW Retic ct
PLT parameters (2)
PLT ct
MPV
heparin color: inversions: lab section: optimal conc: action:
- green top
- 8 inversions
- chemistry, OFT, and ABG
- 15-20 units per mL of blood
- binds antithrombin (inhibits thrombin and factor Xa)
3 formulations of heparin
- ammonium heparin
- sodium heparin
- lithium heparin
3.2% sodium citrate color: inversions: lab section: optimal conc: action:
- light blue top
- 3-4 inversions
- coagulation studies
- AC:blood ratio = 1:9
- chelation of calcium
reference method for Hgb determination
cyanmethemoglobin (HiCN) method
reagent used in HiCN method and its component
Drabkin’s reagent
- potassium ferricyanide
- potassium cyanide
HiCN principle
Hgb + KFeCN > methemoglobin + KCN > cyanmethemoglobin
potassium ferricyanide use:
potassium cyanide use:
- converts hemoglobin to methemoglobin
- provides cyanide ions
HiCN is measured at what nm?
540 nm
all types of Hgb may be measured in HiCN except:
sulfhemoglobin
how many minutes should we allow for the full conversion of hemoglobin into cyanmethoglobin?
10 minutes at room temp
falsely elevated Hgb: -high WBC and PLT ct WBC > 20 000/uL PLT > 700 000/uL correction:
- centrifuge
- measure Hgb at supernatant
falsely elevated Hgb:
-lipemia
correction:
- add 0.01 mL of the patient’s plasma to 5 mL of the cyanmethemoglobin
- use this as reagent blank
falsely elevated Hgb:
-Hgb S and Hgb C
- make a 1:2 dilution with dH2O
- multiply the results from the standard curve by 2
falsely elevated Hgb:
-abnormal globulins
-add 0.1 g of K2CO3 to the cyanmethemoglobin reagent
t or f. cyanmethemoglobin reagent is not sensitive to light.
false. it is photosensitive
handheld system that can measure Hgb conc
HemoCue
Hgb normal range
children:
12-15 g/dL
Hgb normal range
adult female:
12-15 g/dL
Hgb normal range
adult male:
14-18 g/dL
another name for Hgb
respiratory pigment
1 g of Hgb can carry ___ mL of O2
1.34 mL
1 g of Hgb can carry ___ mg of iron
3.47
complete component of adult Hgb molecule (4)
- globin
- protoporphyrin IX (PPIX)
- ferrous iron
- 2,3-BPG molecule
examples of globin chains and their number of amino acids (6)
alpha - 141 aa
zeta - 141 aa
beta - 146 aa
epsilon - 146 aa
delta - 146 aa
gamma - 146 aa
PPIX + ferrous iron =
heme
transcribe 2,3-BPG
2,3-bisphosphoglycerate
where is 2,3-BPG produced?
Rapoport-Luebering Shunt of RBCs
transient resident of hemoglobin
2,3-BPG
purpose of 2,3-BPG
transfers oxygen to tissues
primary functions of Hgb (3)
- delivery of oxygen to the tissues
- carry CO2 away to the lungs
- binding, inactivation, and transport of NO
Hct normal range
newborn
53-65%
Hct normal range
adult females
35-49%
Hct normal range
adult males
40-54%
layers of centrifugated blood
- fatty layer
- plasma layer
- buffy coat
- packed RBC
microhematocrit tube
length:
inner bore:
volume:
- 75 mm long
- 1.2 mm
- 0.05 mL of blood
red band microhct tube
AC:
used for:
- heparin
- collection for non-AC blood
blue band microhct tube
AC:
used for:
- no anticoagulant
- collection for AC blood (EDTA)
microhct procedure blood volume to collect: which side should blood enter: which side should we seal: sealing clay length: microcentrifuge rpm and time: margin of error:
- 2/3
- opposite side of color
- seal at side of color
- 4 to 6 mm
- 10,000 rpm, 5 minutes
- +/- 0.02 L/L
falsely increased hct: (4)
- dehydration
- hemoconcentration
- insufficient centrifugation
- buffy coat was read
falsely decreased hct: (4)
- hemolysis
- improper sealing
- increased AC concentration
- introduction of excess interstitial fluid
purpose of rule of three in CBC
used for checking validity of test results
limitation of rule of three in CBC
works only on normocytic, normochromic specimens
rule of three
Hgb formula:
Hct formula:
3 x RBC ct = Hgb
3 x Hgb = Hct
average volume of an individual RBC
mean cell volume (MCV)
MCV formula
(HCT/RBC ct) x 10
MCV normal range
80-100 fl
average weight or amount of Hgb in an individual RBC
mean cell hemoglobin (MCH)
MCH formula
(Hgb/RBC ct) x 10
MCH normal range
26-32 pg
what is not used in the classification of anemia?
MCH
normal MCV, high MCH
what does this indicate?
falsely increased Hgb (technical error);
MCV and MCH should be paralllel
mean concentration of hemoglobin in the average RBC
mean cell hemoglobin concentration (MCHC)
MCHC formula
(Hgb/HCT) X 100
MCHC normal range
31-37 g/dL
hereditary spherocytosis MCHC
35-38 g/dL
neutrophils
nucleus: cytoplasm: size: progenitor: major stimulatory cytokine:
- 3-5 lobes
- pink w/ violet granules
- 9-15 um
- granulocyte-monocyte progenitor
- granulocyte colony-stimulating factor
3 major functions of neutrophils
- phagocytosis
- generation of neutrophil extracellular traps
- secretory function (transcobalamin I)
eosinophils
nucleus: cytoplasm: size: increases in: primary granules: secondary granules:
- 2 lobes
- bright orange granules
- 9-15 um
- allergies and helminthic infections
- charcot-leyden crystal protein
- major basic protein (core)
which granules of eosinophil is responsible for neutralizing helminths?
major basic protein
basophils
nucleus: cytoplasm: size: progenitor: major stimulatory cytokine:
- difficult to observe
- densely stained w/ purple-black granules
- 10-16 um
monocytes
nucleus:
cytoplasm:
size:
- horseshoe-shaped, stringy chromatin, nuclear vacuoles may be present
- ground-glass appearance (azure dust), blebs may be observed
- 14-20 um
lymphocyte
nucleus:
cytoplasm:
size:
- round, deep-purple
- scanty, sky-blue
- 7-10 um
4 types of WBC diff count
- 100 cell diff
- 200 cell diff
- 300 or 400 cell diff
- 50 cell diff
routinely performed diff count
100 cell diff
performed when the WBC ct is >40 000/uL
200 cell diff
other cases that may need 200 cell diff (4)
> 10% eosinophils
2% basophils
11% monocytes
more lymphocytes than neutrophils (except in children)
performed when the WBC ct is >100 000/uL
300 or 400 cell diff
performed when the WBC ct is 1 000/uL
50 cell diff
what smear is used for 50 cell diff?
buffy coat smear
gives the number of specific WBC type per 100 WBCs; not as informative and accurate
relative count
relative count % formula
(no of specific WBC type/100 WBCs counted) x 100
relative count normal range
N = 51-67% L = 25-33% M = 2-6% E = 1-4% B = 0-1%
gives the number of specific WBC type per uL; more informative and accurate
absolute count
absolute count % formula
relative count x WBC count
absolute count normal range
N = 1 600-7 260/uL L = 960-4 400/uL M = 180-880/uL E = 45-440/uL B = 45-110/uL
