Important Do’s & Don’ts (When Drawing Blood From All Animals)

The quality of your results are only as good as your samples

Restraint time effects Blood Chemistry:

From the moment you disturb any animal in it’s cage it becomes afraid. This fear reaction causes an increase in the Corticosterone level secreted by the Adrenal Cortex, which intern will elevate Glucose and lower Insulin levels as the mouse prepares for “Fight or Flight.”

If your are monitoring mice for Diabetes, or other studies that might be adversly affected by this, make sure you are as quick as possible from when you first disturb the animal’s envirement to when you finish drawing the blood sample.

MEDIpoint’s Goldenrod Animal Lancets are much faster than other methods of drawing blood, especially in Mice where R.O. Bleeding now requires use of anesthetic, which dramatically increases the the animal’s time out of it’s cage.

Keep Hemolysis Low:

When drawing blood from any animal, it is important to let the drops fall freely, undisturbed, as quickly as possible from the bleeding sight to the collection container, avoiding as much Cell Damage (Hemolyses) as possible. Often you can tell at a glance which chemistry samples have a high level of Hemolysis by the reddish tinge caused by the ruptured red blood cells. The clearer the sample, the less hemolysis there is.

Why is hemolysis so bad? When red blood cells rupture, heme and enzymes are released into the sample matrix which adversely affects many of the tests we run on mice, such as Bilirubin, electrolytes, muscle and liver enzymes, and colorimetric assays. Most often, results are falsely elevated. If you are not getting notations from your lab about the presence of hemolysis, your data could be skewed. You may think that you are discovering a new strain of mouse model for liver disease or muscular dystrophy when, in fact, you are only truly observing the results of bad samples, with too much Hemolysis.

There is generally much more incidence of hemolysis with the RO bleeding technique probably due to the capillary tube. The blood is forced down this narrow tube from the venous plexus causing some cells to rupture.

MEDIpoint’s Goldenrod Animal Lancets allow an undisturbed rapid flow of blood from the animal’s bleeding sight to the collection tube to minimize any hemolysis. Good technique suggests that you only let the drops fall freely into the collection tube. Do not rub the collection tube against the puncture site to try to capture one or two more drops. Better to move the head slightly up and down to keep the wound open, and blood flowing, to avoid any hemolysis.

Avoid Platelet Clumping:

Platelet Clumping (Clotting) is caused by the activation of platelet factors. Mice, for example, have 3 to 4 times as many platelets as humans, and thus a lot more platelet factors to excite and activate. It has been speculated that mice have so many platelets because they are a prey animal. Therefore, any wounds must be closed quickly for a chance of survival. This makes collecting a nice, anticoagulated sample to run through hematology analyzers quite challenging.

The proper way to collect the blood, to avoid as much platlet clumping as possible, is to let the drops free fall quickly into the collection tube. This not only reduces the platlets exposure to oxygen in the air, but the blood is also mixes quickly with any anticoagulant, which may be present in the collection tube.

The reason there is a high incidence of platelet clumping with the RO technique is probably due to the capillary tube. Often clotting occurs even when using anticoagulated capillary tubes. This is because each capillary tube is designed to anticoagulate only 75 uL of blood. If you need a larger sample, say 200 uL, for your hematology analysis; the anticoagulant has long since been used up before you are finished drawing your sample.

MEDIpoint’s Goldenrod Animal Lancets do not require the use of capillary tubes. The blood flows freely and quickly into the collection tube where it can instantly mix with the antiqoagulant.