Cleveland Family Study

3.5 Venipuncture

3.5.1 Preparation

3.5.1.1 Preparation of Participants for Phlebotomy

Informed consent must have been obtained before blood is drawn at the first draw (10:30 PM evening draw). It should be stressed that this study requires the voluntary cooperation of the participants. Although these people receive a small compensation for their time, participation in this study and blood donation is purely voluntary, with no reward other than the knowledge that they are contributing to progress in medicine. Thus, the whole experience must be made as pleasant as possible. Four tubes of blood of various sizes are collected, each containing about 1-2 teaspoons (5-10mLs) of blood.

Blood drawing is standardized for the supine position for the 10:30 PM and 8:00 AM draws. The 10:00 AM post-OGTT draw will be in a seated position. The venipuncture is performed with a 21 gauge butterfly needle with 12 inches of plastic tubing between the venipuncture site and the blood collection tubes. The butterfly has a small, thin walled needle that minimizes trauma to the skin and vein. The use of 12 inches of tubing allows tubes to be changed without any movement of the needle in the vein. The participant should be given enough time to feel comfortable both before and after the blood collection. The participant should spend at least 10 minutes in a supine or seated position before blood is drawn. In many cases the most memorable part of the experience for the participant will be the contact with the technicians who draw the blood and their general attitude and competence. DO NOT under any circumstances force the participant to have blood drawn.

3.5.1.2 Phlebotomy/Processing Rooms

The blood drawing (all three draws) takes place in the patient’s room at the GCRC. The room is equipped with all of the necessary blood drawing supplies. A plastic tray or cart is equipped with all of the materials and vials that are used in the blood drawing procedure. A separate processing room contains an area for processing activities and the centrifuge, refrigerator, and freezer required for handling and storage.

3.5.1.3 Priority of Tubes

A total of approximately 30 mL of blood will be drawn from each participant in 4 tubes at both the evening (10:30 PM) and first morning (8:00 AM) draws. For blind duplicates, 20% of the participants will have 5 tubes collected for a total of 35 mL of blood.

The order in which the tubes are collected is important. Blood collection must be drawn in the following order:

1. 10 mL Serum – red top
2. 5 mL Citrate – blue top
3. 10 mL EDTA – purple top
4. 5 mL SCAT-1 – red top

An additional 5 mL of blood will be drawn in the morning (10:00 AM) after glucose loading using a 5 mL Serum tube.

3.5.1.4 Summary of Blood Mixing During Venipuncture

Each tube should be treated as follows:

• Tube #1 – Serum. DO NOT MIX. Place in rack at room temperature for AT LEAST 40 minutes, but no longer than 90 minutes.
• Tube #2, #3, and #4 – Place on mixer for approximately 30 seconds, then place in ice bath.

3.5.1.5 Setup of Draw Tube and Aliquot Racks

To facilitate accurate tracking of collected specimens, we recommend that you set up a blood collection tube rack with the set of draw tubes, pre-labeled with the provided participant ID labels. The tubes should be in the rack according to the order in which they are to be drawn, as specified above. An aliquot rack, with pre-labeled cryovials, should be set up to correspond with each participant’s blood collection tube rack. It may be helpful to have the serum cryovials and tubes per participant in a separate rack since the red serum collection tubes are generally centrifuged at a different time from the other tubes.

3.5.1.6 Preparation for Specimen Collection

Preparation for specimen collection is done in the following manner. Prior to arrival of any participants:

1. Make sure venipuncture supplies are stocked and the tubes and cryovials are labeled.
2. Check that the sample processing station is properly equipped. Every item on the checklist must be ready and in its proper position.
3. Make sure the phlebotomy tray or cart is tidy and stocked with extra smelling salts, basin, wash cloths, and that the draw tube mixer is functional.
4. Label the tubes and cryovials with the Participant ID (if not previously done).
5. Approximately 10 minutes before scheduled blood specimen collection, fill styrofoam ice bath ¾ full with crushed ice.

3.5.1.7 Phlebotomy Form Questions

There are three questions to ask the participant before the start of venipuncture at the first draw (10:30 PM). These questions deal with the participant’s experience with venipuncture. If they answer yes to any of these three questions, the phlebotomist can take extra care with the procedure at the first and subsequent draws.