# B A L

Μηχανική

22 Φεβ 2014 (πριν από 7 χρόνια και 8 μήνες)

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B
LOOD

A
NALYSIS

L
AB

Things to Know

H
EMATOCRIT

D
ETERMINATION

Hematocrit

refers to % of RBCs in a sample of
whole blood

A
hematocrit

of 48 means that 48% of the volume
of blood is red blood cells

The higher the
hematocrit
, the more RBCs
present in the sample

Hematocrit

is determined by spinning a
microcapillary

tube filled with a whole blood
sample in a special
microhematocrit

centrifuge.

This procedure separates blood cells from the
plasma and leaves a “
buffy

coat” layer of WBCs
between the heavier RBC layer and the lighter
plasma

D
ETERMINING

THE

HEMATOCRIT

VALUE

After centrifuging, measure the height of the
layer of RBCs in mm and divide by the height of
the initial column of blood to obtain the
percentage of RBCs

The percentage of WBCs can be determined by
comparing the height of the
buffy

coat to the
initial height of the blood column.

The average
hematocrit

for males is 47% and
42% for females

The upper limit is 55%

Lower than normal
hematocrit

= anemia

Higher than normal
hematocrit

=
polycythemia

Anemia

a condition in which insufficient
oxygen is transported to the body’s cells

Polycythemia

a condition caused by living at
high altitudes,
strenous

athletic training, and
tumors in the bone marrow

E
RYTHROCYTE

S
EDIMENTATION

R
ATE

(ESR)

Measures the settling of RBCs in a vertical,
stationary tube of blood during one hour

In a healthy individual, ESR only about 5 mm/hr

High ESRs indicate disease due to clumping
together of cells making them heavier and settle
faster

ESRs can be used to measure progression of a
disease (increase

worse; decrease

better)

Can be used to distinguish between angina
pectoris to myocardial infarction

H

(
HB
)
DETERMINATION

Used to determine possible causes of anemia

Normal blood contains average of 12
-
18 grams of
hemoglobin per 100 mm of blood

Increase occurs at high altitudes,
polycythemia
,
congestive heart failure, and chronic obstructive
pulmonary disease (COPD)

Decrease occurs with anemia, hyperthyroidism,
cirrhosis of the liver, renal disease, systemic
lupus
erythematosus
, and severe hemorrhage

Hb

content determined by stirring a sample of
blood with a wooden stick to break or
lyse

the
cells.

The intensity of the color of the color of the
sample is a result of the amount of
Hb

present

A
hemoglobinometer

compares the color of the
sample to standard values to determine the
hemoglobin content of the sample

Green light is used to view the sample because
the human eye is able to easily detect subtle
differences in green colors

B
LOOD

TYPING

Type

Antigens

Antibodies

A

A

Anti
-
B

B

B

Anti
-
A

AB

A and B

None

O

Neither A nor B

Anti
-
A, Anti
-
B

B
LOOD

T
YPING

Type

Donate

A

A, AB

A, O

B

B, AB

B, O

AB

AB only

A, B, AB, O

O

A, B, AB, O

O only

AB is the universal
recepient

O is the universal donor

R
H

FACTOR

Antigen discovered in Rhesus monkeys

If present,
Rh
+

If absent,
Rh
-

Rh
-

blood can be given to
Rh
+, but
Rh
+ cannot be
given to
Rh
-

Erythroblastosis

fetalis
: condition threatening
life of baby; occurs when baby is
Rh
+ and mother
is
Rh
-

Mother’s anti
-
Rh

antibodies
might

attack baby’s
RBCs

C
HOLESTEROL

Lipid substance essential for life

Important component of cell membranes, basis for
making steroid hormones, vitamin D, and bile salts

Produced in the human liver

Present in some foods of animal origin (milk, eggs,
meat)

Water insoluble, needs to be wrapped in protein
packages called lipoproteins to travel in the watery
blood from the liver and digestive organs to the cells
of the body

LDL (low density lipoprotein) is potential source of
damage to arteries causing plaque buildup; “bad
cholesterol”

HDL (high density lipoprotein) is “good cholesterol”

C
HOLESTEROL

D
ETERMINATION

Blood sample mixed with enzymes that produce a
colored reaction with cholesterol

Intensity of the color indicates the amount of
cholesterol present

Measured in mg/deciliter of blood

200 mg/deciliter = desirable

200
-
239 mg/deciliter = borderline high cholesterol

240 mg/deciliter = high blood pressure

“silent
-
killer” = can cause heart attack/stroke

Low levels may
indicate hypothyroidism