Protocol Number: 04-CC-0046

Title:

Citrate Effects and Bone Density Studies in Long-Term Apheresis Donors

Number:

04-CC-0046

Summary:

This study will examine the effects of repeated apheresis procedures on bone density and calcium balance. Apheresis is a procedure for collecting large numbers of a specific blood component, such as white cells (leukapheresis) or platelets (plateletpheresis). For the procedure, whole blood is collected through a needle in an arm vein and is directed through a machine that separates it into its components by spinning. The desired cells are removed and the rest of the blood is returned to the donor, either through the same needle or through a needle in the other arm. A blood thinning medicine called citrate is added to the cell-separating machine. Citrate reduces the ionized calcium levels in the blood, which prevents the blood from clotting. When the blood is returned to the donor, the donor also receives the citrate. This lowers the donor's ionized calcium levels which may irritate nerve and muscle cells, causing tingling around the mouth, hands, and feet during the procedure. The reduced ionized calcium levels result in increased parathyroid hormone levels in the donor, can effect bone calcium stores. In addition, some of the citrate that is returned to the donor is excreted in the urine along with calcium, which causes further loss of calcium from the body. It is not known if the calcium loss during apheresis in people who undergo this procedure repeatedly has any long-term effects on body calcium balance and bone calcium stores. This study will measure bone density and calcium balance in long-term platelet and white cell donors and compare the findings with those of whole blood donors, who do not receive citrate.

Healthy people between 18 and 80 years of age who weigh between 110 and 300 pounds, do not have a metal prosthesis, and are not pregnant may be eligible for this study. Participants undergo the following procedures:

Whole blood donors

- Blood sample collection 2 weeks before blood donation.

- I removed undergo standard whole blood donation

-Urine sample collection.

- DEXA scan to assess bone density by measuring bone calcium stores. For this procedure, the subject lies still on a table while the spine, hip, and whole body are scanned using a small amount of radiation. The forearm is also scanned while the subject is seated. The scan may be repeated after 2 years.

Plateletpheresis and leukapheresis donors

- Standard platelet or white cell donation.

- Blood sample collections immediately prior to and after donation, and on the first, fourth, and fourteenth days after donation.

- Urine sample collections at the beginning and at the end of the apheresis procedure and on the first, fourth, and fourteenth days after the donation.

- DEXA scan at the beginning of the study (no earlier than 2 weeks after their latest apheresis donation). The scan may be repeated after 2 years.

- Some apheresis donors may be asked to have a second procedure in which they take calcium according to standard guidelines for plateletpheresis and leukapheresis. During the second procedure, platelet donors will take oral calcium tablets before starting plateletpheresis. White cell donors will receive calcium intravenously (through a vein) during the second leukapheresis. For this second procedure, the donors provide additional blood and urine samples as described above.

Sponsoring Institute:

National Institutes of Health Clinical Center (CC)

Recruitment Detail

Type: Completed Study; data analyses ongoing

Gender: Male & Female

Referral Letter Required: Yes

Population Exclusion(s): Children

Eligibility Criteria: This study is not currently recruiting new subjects. If you have questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.

Special Instructions:

Currently Not Provided

Keyword(s):

Plateletpheresis

Lymphocytapheresis

Apheresis

Citrate

Bone Density

Recruitment Keyword(s):

Healthy Volunteer

HV

Condition(s):

Blood Component Removal

Investigational Drug(s):

None

Investigational Device(s):

None

Interventions:

None

Supporting Site:

Warren G. Magnuson Clinical Center

Contact(s):

This study is not currently recruiting new subjects. If you have questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.

Citation(s):

Hester JP, McCullough J, Mishler JM, Szymanski IO. Related Articles, Links No abstract Dosage regimens for citrate anticoagulants. J Clin Apheresis. 1983;1(3):149-57. No abstract available. PMID: 6546053

Hester JP, Ayyar R. Related Articles, Links No abstract Anticoagulation and electrolytes. J Clin Apheresis. 1984;2(1):41-51. No abstract available. PMID: 6536658

Dzik WH, Kirkley SA. Related Articles, Links No abstract Citrate toxicity during massive blood transfusion. Transfus Med Rev. 1988 Jun;2(2):76-94. Review. No abstract available. PMID: 2980082

• Questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.
• Technical questions regarding the Clinical Center web site, please contact the Department Clinical Research Informatics, CC.

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