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Office of Research Integrity

Sampling Guidelines

Tail Tissue Sampling

Tail snipping for DNA analysis may be performed in mice <24 days of age without anesthesia provided the sample size is <1cm. For mice 24-30 days of age a 0.5 cm sample size may be taken without anesthesia. Orbital sinus blood sampling may be performed for DNA analysis in animals <30 days of age without anesthesia. Variations from this policy require scientific justification to be submitted to the IACUC. (08/09)

Blood Sampling

Estimate the animal's total blood volume based on body weight to determine blood sampling volumes in research animals.

Average Blood Volumes of Research Animals Based on Body Weight

SpeciesWhole Blood Volume (ml/kg)% Body WeightPlasma Volume (ml/kg)Approx. Absolute Blood Volumes of Animals of Described Weight
Mouse75 (70-80)30-g mouse: 2.3 mlc
Rat64 (58-70)6.440 (36-45)300-g rat: 20 ml
Hamster72.5 (65-80)100-g hamster: 7.25 mlc
Gerbil72.5 (60-85)90-g gerbil: 6.5 mlc
Guinea Pig75 (67-92)7.540 (35-48)90-g guinea pig: 68 ml
Rabbit56 (44-70)5.539 (28-51)3.2 kg rabbit: 180 ml

56 (47-66)


41 (35-52)
4.5 kg (10 lb.) cat: 252 ml
4.5 kg (10 lb.) cat: 300 mla
4.5 kg (10 lb.) cat: 194 mlb
Dog868.65014-kg (30 lb.) dog: 1200 ml

Guidelines for single sampling:

  • Maximum of 15% of total blood volume with 30 day recovery period. Justification is required for taking volumes greater than 15%.

Guidelines for multiple samplings:

  • Maximum of 7.5% of total blood volume if bled weekly.
  • Maximum of 10% of total blood volume with 2 week recovery period if bled every 2 weeks.
  • Hematocrit should be monitored and the frequency of sampling decreased if the PCV falls below 35%

Note: All values are from Altman and Dittmer (1974) unless otherwise specified.

aJain, N.C.
bBreznock, E.M.
cOlfert, E.D.