Plasma Volume Determination by 99mTc-labeled Albumin and 125I-labeled Albumin

For many years, radioiodinated albumin has been "the golden standard" for measurement of plasma volume. There are a number of clinical situations in which a nuclide with a shorter half-life would be preferred. Furthermore, due to periodic lapses in the availability in the delivery of 125I-labeled albumin, there is a need to evaluate another nuclide as a tracer for plasma volume determination.

99mTc-labeled albumin is easily prepared by a simple and reproducible method with a high labeling efficiency and short half-life.

In this study, we want to compare plasma volume determined by 99mTc-labeled albumin with plasma volume determined by 125I-albumin (golden standard). In both procedures, plasma volume is estimated from multiple postinjection samples for accurate zero-time extrapolation in order to correct for leakage of labeled albumin from the vascular compartment.

• Plasma volume determination (99mTc-albumin) (Radiation): The test is performed using 5MBq technetium-labeled albumin (99mTc-albumin-Vasculosis) with several postinjection samples for accurate zero-time extrapolation.
• Plasma volume determination (125I-albumin) (Radiation): The test is performed using 0.2MBq 125iodine-labeled albumin (125I-albumin) with several postinjection samples for accurate zero-time extrapolation.

Primary outcomes

• Plasma volume determined by 99mTc-labeled albumin and 125I-labeled albumin [January 2011]

Secondary outcomes

• Rates of loss of 99mTc-labeled albumin and 125I-labeled albumin from the circulation [January 2011]

Sex: All, ages: 18 Years to 75 Years, accepts healthy volunteers

Inclusion Criteria:

* BMI < 27 kg/m2
* Written informed consent

Exclusion Criteria:

* Hypertension (140/90 mmHg)
* Diabetes mellitus
* Any use of medication
* Pregnancy

• Steen Levin, MD, DMSc, Study chair, Zealand University Hospital
• Peter K Bonfils, MD, Principal investigator, Zealand University Hospital
• Knud H Stokholm, MD, Study director, Zealand University Hospital