Biotin Labeling of Red Cells in the Measurement of Red Cell Volume in Preterm Infants

Abstract

ABSTRACT. Determination of circulating red cell volume (RCV) in anemic preterm infants is, in theory, a better indicator of transfusion needs than Hb concentration. Our study reports the results of RCV measurement using biotin labeling of red cells on 40 occasions in preterm infants of 25-34 wk gestation. In 20 infants, who had estimations made within 24 h of birth, the RCV varied between 17.7 and 66 mL/kg. Twenty measurements were made at a later age at the time of a blood transfusion. RCV values were between 13.1 and 41.5 mL/kg before transfusion. In 13 infants, RCV was determined simultaneously using two methods, biotin and dilution of autologous HbF with donor HbA at transfusion. There was no significant difference between the results of RCV estimations using these two methods. Our study demonstrates that biotin labeling is an effective method for determining RCV in preterm infants. The RCV represents the total volume of red cells in the circulation. It has been suggested that the RCV is a better guide to red cell transfusion requirements than Hb concentration (l-3), which has been shown to be a poor predictor of benefit from blood transfusion (4-6). After acute blood loss and in anemia of prematurity, the Hb concentration is poorly correlated with RCV; some infants have a very low RCV, yet maintain an adequate Hb concentration (1, 2, 7). RCV may also be a more rational physiologic indicator than Hb concentration of the oxygen carrying capacity of the blood in the whole circulation (3). Low RCV at birth is associated with birth asphyxia (8, 9), increasing severity of hyaline membrane disease (9, lo), and increased mortality (8, 10). RCV estimation has become a vital investigation in adults with polycythemias, some anemias, and the assessment of erythropoiesis (1 1).Previously described methods for determining RCV include both techniques using the dilution principle after labeling of red cells with a tracer and indirect methods, which give a calculated RCV derived from plasma volume and Hct. Radioisotopes as tracers (1 1 iably to overestimate plasma volume. Accurate calculation of RCV from plasma volume requires not only accurate plasma volume estimation but also a knowledge of the total body Hct. Although correction factors allow for the difference between venous and total body Hct (14, 15, 16), they are of quite unknown reliability in sick infants. RCV can be estimated using dilution of autologous HbF at the time of a blood transfusion (2, 17). This is reliable provided that HbF estimation is accurate (e.g. alkali denaturation technique) (2) and at least 20% of the Hb in the circulation before transfusion is fetal. This technique cannot be used without a donor blood transfusion.A new method has recently been described for determination of RCV in adults. Biotin is used to label autologous red cells, and their dilution is quantitated in a fluorescence-activated cell sorter using the fluorescein-streptavidin reaction (17). Biotin is not toxic in infants, even in pharmacologic doses (1 8).We report here results...

Changes in circulating red cell volume during the first 6 weeks of life in very-low-birth-weight infants

“…The mean RCV in our patients, 35.7 ml/kg soon after birth and 21.6 ml/kg at 6 wk, is similar to the results previously reported for newborn infants (1,4,5,7,8,10,11).…”

“…Nevertheless, the use of radioactive substances for research in infants would be considered ethically unacceptable in the 21st century. Fortunately, biotin has been developed as a safe, nonradioactive RBC label for studies of RCV and RBC survival in infants (10,11,14,24,25), allowing continued research in this important area.…”

“…Others have subsequently reported their experiences measuring RCV directly using chromium-51 ( 51 Cr) (2-6), chromium-50 ( 50 Cr) (7), technitium-99 ( 99 Tc) (8), and biotin (9)(10)(11) as red blood cell (RBC) labels. In addition, several other methods have been used to calculate RCV based on changes in fetal hemoglobin concentration (12)(13)(14) or mismatched RBC antigens (14,15) following a transfusion of packed RBCs, or by calculation from measured plasma volume and hematocrit (16).…”

A New Method for the Measurement of Cerebral Blood Volume and Total Circulating Blood Volume Using Near Infrared Spatially Resolved Spectroscopy and Indocyanine Green: Application and Validation in Neonates

“…The availability of a simple cotside method to estimate TCV that could be used shortly after birth would be a useful tool both for the neonatal clinician and the researcher. Methods used previously involving the injection of autologous red cells labeled with biotin (3) or repeated blood sampling following injection of a marker such as indocyanine green (4) are not suitable for routine clinical practice.…”

Biotinylation: A Nonradioactive Method for Labeling of Blood Components

“…However, this is in contrast to the in vivo labeling of platelets in mice with NHS biotin and NHS-LC biotin, because no difference of the life span could be detected [9]. Also in preterm infants, the biotin labeling technique was used for the measurement of red-cell volume [10]. Red-cell volume was determined simultaneously using the biotin technique and the dilution of fetal hemoglobin (HbF) with donor HbA at transfusion.…”