Texas Health Steps: Specimen Collection and Handling

This blood collection tube is used for total hemoglobin and lead testing for the THSteps program. The tube displayed is the DSHS Laboratory-specified blood collection tube accepted for testing. It is provided by the DSHS Laboratory. We will also accept 3 mL and 4 mL tubes from the same manufacturer. The fill volume for each tube is stated at the bottom of the label.

Note the black mark on the edge of the label. Some tubes may have different color labels and markings. The mark on the edge of the label (see arrow on picture) indicates the approximate volume that the tube is designed to collect. Tubes that are designed to draw 3 mL or 4 mL will have this mark closer to the top of the tube.

The tubes are displayed to indicate the minimum and maximum acceptable volumes. Use the Purple Top Tube Guide (available from the Container Preparation department) to assist in obtaining the correct volume for each size of Vacutainer tubes. NOTE: Do not reproduce the Purple Top Tube Guide; for original copies, contact the Container Preparation Department.

Remember that the 2 mL Vacutainer blood collection tubes have a low vacuum on them as they are designed to draw only 2 mL of blood. This means that blood will flow more slowly into the tube and the draw may take longer to obtain the desired volume of blood.

There are three options for obtaining the correct volume for the Vacutainer tubes.

1. Typical venipuncture technique using a Vacutainer tube and a multidraw needle. The tube is designed to draw ~2 mL of blood. Do not remove the needle from the vein too soon or the vacuum of the tube will not have sufficient time to draw the correct volume. Once the draw is complete, compare it to the 2 mL diagram on the Purple Top Tube Guide to ensure the volume meets DSHS requirements.
2. Venipuncture using a “butterfly”collection device with a Vacutainer tube. Once the “butterfly” device is attached to the tube, the “dead space” in the “butterfly” tubing will evacuate enough of the vacuum in the Vacutainer tube that it can no longer pull the desired volume. Avoid this problem by using a “waste” or “discard” tube – attach the “butterfly” to the tube and perform the venipuncture; once a small amount of blood is drawn into the Vacutainer, remove the “waste” or “discard” tube and replace it with a second Vacutainer that has not had its vacuum compromised. At this point, the second Vacutainer should pull the correct volume. Again, do not remove the needle from the vein too soon or the vacuum of the tube will not have sufficient time to draw the correct volume. Compare to the Purple Top Tube Guide to ensure the correct volume has been met.
   Another way to perform this action without use of a “waste” or “discard” tube is to attach the blood collection tube to the “butterfly” collection device once blood is flowing into the tubing.
3. Venipuncture using a syringe and “butterfly” collection device. This option allows the phlebotomist to use the “butterfly” device but uses a syringe of appropriate size to draw sufficient blood in order to meet the fill volume requirement for the blood collection tube to be used. For example, if a 2 mL Vacutainer will be used, a 3 mL syringe may be used to draw ~2.5 mL of blood. Then, using the Purple Top Tube Guide, the correct amount of blood can be dispensed back into the 2 mL Vacutainer. If a 3 or 4 mL Vacutainer will be used, a 5 mL syringe may be used to draw ~3.5 or 4.5 mL of blood, respectively.

This blood collection tube is used for total hemoglobin and lead testing for the THSteps program. The tube displayed is the DSHS Laboratory-specified fingerstick (sometimes called capillary) tube accepted for testing. It is provided by the DSHS Laboratory.

The tubes are displayed to indicate the minimum and maximum acceptable volumes. For this tube, the minimum and maximum acceptable volumes are indicated on the tube by the 250 and 500 µL lines. The blood level must be anywhere between these two lines to be acceptable for fill volume. Avoid getting the blood level right at the 250 or 500 µL lines as this volume can be misinterpreted upon receipt at the DSHS Laboratory and determined unacceptable.