Since the mid-1960s nuclear medicine laboratories have been performing total circulating blood volume analysis with chromium-51 ascorbic acid method for labeling red blood cells and I-125 human serum albumin for plasma volume estimation. This non-imaging nuclear medicine test has great benefits for many types of patients including congestive heart failure, polycythemia vera, neurology, trauma patients and more. While being a slow and arduous process exposed to technical errors and varying results, the test slowly stepped out of the limelight.
In addition, securing a constant supply for Chromium-51 has been challenging. Now, a new FDA approved semi-automated medical device offers consistent and accurate results without using Chromium-51. This revitalization of blood volume analysis aligns with Centers for Medicare and Medicaid Services' new implementation of outcome measures denying reimbursement for readmission of congestive heart failure patients within 30 days of discharge.
Patients may have too many solids or too much plasma in their blood and physicians need to determine if diuretics or packed red blood cells should be administered to attain euvolemia. Hematocrits alone do not provide the true answer since it tells the difference between percentages of solids to liquid in the blood's volume. For example, elevated white blood cells can alter the results contributing to the false appearance of normal red blood cell values.
Daxor offers blood volume analysis using 25µCi of iodine-131 human serum albumin with five blood draws for an accurate representation of blood and plasma volume. The protocol requires the patient receive the injection and after 12 minutes for the dose to circulate, blood draws begin. Five blood draws are performed six minutes apart with the exact time of the blood draw documented. If a blood draw is off schedule by a few minutes, it will not compromise the test results. With a greater number of blood samples there is a greater accuracy and reproducibility of the test result.
In contrast, the traditional dual isotope method uses Chromium-51 ascorbic acid to label red blood cells and Iodine-125 human serum albumin to estimate plasma volume. This procedure requires three or four intravenous catheters to be placed in the patient--two for injecting and two for withdrawing blood. 10 mL of venous blood is withdrawn from the patient and then tagged with 30 µCi of 51Cr and with of 50 mL ascorbic acid added to stop the tagging process; 5 mL of the blood is then re-injected back into the patient. After 10 minutes, a blood sample is withdrawn from the patient in the other side of the patient's body that was used for injection. Patients with severe polycythemia vera or splenomegaly will require additional blood draws due to the slow mixing time in the body. Next, the plasma volume estimation protocol.
Iodine-125 human serum albumin is injected into another IV access in order to prevent possible trace re-introduction of the prior isotope still remaining in the IV catheter. Blood draws are 10, 20, and 30 minutes post injection. The exact time of the specified blood draws must be strictly adhered to or the test results will be compromised.
For both methods of blood volume analysis, centrifuge and calculations will take approximately 90 minutes or longer for the dual isotope method to perform to obtain the final results.
Recently, Daxor introduced a new business model for its advanced technology to nuclear pharmacies that hold an FDA's Clinical Laboratory Improvement Amendments (CLIA) license to overcome hospitals obstacles who could not offer blood volume analysis. These obstacles include the hospital's FDA's Clinical Laboratory Improvement Amendments (CLIA) license, contractual, cost, and staffing obstacles. Hospitals realized a benefit of this technology but could not offer it.
Your hospital may be able to benefit from this new business model which uses the hospital's nuclear pharmacy vendor to deliver Daxor's Volumex® Human Serum Albumin I-131 Single Unit Dose Injectate with Prepackaged Collection Kit. The vendor will use Daxor's equipment in its laboratory to spin the blood down and provide the final report. In addition, this test adds another procedure to your department (think staff jobs) all while serving congestive heart failure patients and more, reducing CCU/ICU days saving the hospitals money, and best of all reducing patient re-admits. Everyone benefits.
1. Shertech Pharmacy in the Carolinas was the first nuclear pharmacy in the country to partner with Daxor.
3. Nuclear Medicine and PET/CT Technology and Techniques, edited by P.E. Christian and JM Waterstram-Rich, 2007 p 598. Mosby
4. Blood Volume Analysis: A New Technique and New Clinical Interest Reinvigorate a Classic Study*; TA. Manzone, et al. Nucl. Med. Technol. June 2007 vol. 35 no. 2 55-63
Cindi Luckett-Gilbert, MHA, CNMT, PET, FSNMTS, is PET specialist for Shertech Pharmacy.