RBC indices

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

RBC indices

Definition:

Red blood cell (RBC) indices are part of the complete blood count (CBC) test. The indices include:

Average red blood cell size (MCV)
Hemoglobin amount per red blood cell (MCH)
Hemoglobin concentration (hemoglobin amount relative to the size of the cell) per red blood cell (MCHC)

text continues below

Red blood cells transport hemoglobin which, in turn, transports oxygen. The amount of oxygen received by tissue depends on the amount and function of RBCs and hemoglobin. The MCV, MCH, and MCHC reflect the size and hemoglobin content of individual red blood cells.

See also RBC count.

Alternative Names:
Erythrocyte indices; Blood indices; Red cell mass measurement; MCH (mean corpuscular hemoglobin); MCHC (mean corpuscular hemoglobin concentration); MCV (mean corpuscular volume)
How the test is performed:

Blood is drawn from a vein, usually on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to swell with blood.

A needle is inserted into the vein, and the blood is collected in an airtight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

For an infant or young child, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.

The values for MCHC, and MCH are derived from the hemoglobin (Hgb), hematocrit (Hct), and red blood cell count (RBC) by mathematical calculations:

MCHC = Hgb/Hct
MCH = Hgb/RBC

The MCV is measured directly.

How to prepare for the test:

No special preparation is necessary.

For infants and children, the preparation you can provide for this test depends on your child's age and previous experience. For general information regarding how you can prepare your child, see the following topics: