DREXEL UNIVERSITY ANIMAL CARE AND USE COMMITTEE
POLICY FOR ANIMAL BLOOD VOLUME SAMPLING
OBJECTIVE
The Drexel University Animal Care and Use Committee has established this policy to
specify the maximum blood sampling volumes which can be obtained without having an
adverse effect on research animals.
RESPONSIBILITY
The Investigator is responsible for ensuring that each individual obtaining blood from
animals follows this policy. ULAR is responsible for providing training on the
appropriate methods for obtaining blood samples from various species of animals.
BACKGROUND
Moderate (10-20%), and even small (less than 10%) blood loss can have profound
physiologic effects on research animals. Effects may be species, age and sex dependent
and, if not taken into account, may affect the outcome of experiments. Effects may
include reduction in cardiac output [50% in rats with 15% blood loss], change in
anesthesia metabolism [due to decreased perfusion of the liver in dogs with 6% blood
loss], and a number of other documented changes. (McGuill, MW and Rowen, AN,
Biological Effects of Blood Loss: Implications for Sampling Volumes and Techniques,
ILAR News, Volume 31, No. 4, Fall, 1989.)
PROCEDURES
Table 1 presents limit volumes and recommended recovery times for both single and
multiple sampling regimes. These values do not include a terminal sample, which can be
taken when the animal is terminally anesthetized.
Table 1
Limit Volumes and Recovery Periods
Single Sampling
% Circulatory
Blood Volume
removed
7.5 %
10 %
15 %
Approximate
Recovery period
1 week
2 weeks
4 weeks
Multiple Sampling
% Circulatory Blood
Volume removed in a
24 hour period
7.5 %
15 %
20 %
Approximate
Recovery
period
1 week
2 weeks
3 weeks
Using the values from Table 1, guidelines for blood volumes removed without significant
disturbance to the animal’s physiology are presented in Table 2.
Table 2
Total Blood Volumes and Recommended Maximum Blood Sample Volumes
Species (weight)
Mouse (25 g)
Rat (250 g)
Rabbit (4 kg)
Ferret (1.5 kg)
Dog (10 kg)
Minipig (15 kg)
Blood
Animal’s
Volume Total
(ml/kg) Blood
Volume
(mls for wt
shown)
72
1.8
64
16
56
224
75
112.5
85
850
65
975
7.5 %
(ml)
10 %
(ml)
15 %
(ml)
0.1
1.2
17
8.4
64
73
0.2
1.6
22
11.3
85
98
0.3
2.4
34
16.9
127
146
MULTIPLE SAMPLES
If multiple samples are required over a 24-hour period, a maximum of 1.0% of an
animal’s total circulating blood volume may be removed.
Multiple sampling is best achieved through a temporary cannula, reducing pain and
distress in the animal.
FLUID REPLACEMENT
Fluid replacement after removal of 10% or greater of a healthy, normal, adult animal’s
total blood volume on a single occasion is highly recommended. Fluids should be
isotonic and warmed. Fluids can be given subcutaneously
HEMATOCRIT (PACKED CELL VOLUME/PCV)
By monitoring the hematocrit (or packed cell volume-PCV) and/or hemoglobin of the
animal, it is possible to evaluate whether the patient has sufficiently recovered from a
single blood draw or multiple blood draws. After a sudden or acute blood loss, it takes up
to 24 hours for the hematocrit and hemoglobin to reflect this loss. This means that after a
1% of body weight blood loss without fluid replacement, an animal's hematocrit will not
show a measurable drop for several hours, and will not stabilize for 24 hours. After 24
hours although the blood volume will normalize, the number of red blood cells
(hematocrit) will be measurably reduced. In general, if the animal's hematocrit is less
than 35% or hemoglobin concentration is less than 10 g/dl it is not safe to remove the
volume of blood listed above.
TERMINAL SAMPLES
Blood samples taken from animals that will not recover from anesthesia are not covered
by this policy.
Approval date: December 2003
Last review date: April 2015