Evaluation of a microspectrofluorimetric method or serum vitamin A.

A microspectrofluorimetric method for vitamin A was compared with spectrophotometric and trifluoroacetic acid-colorimetric procedures. Values obtained by the fluorimetric method showed a high degree of correlation with those obtained by other standard procedures. However, it was found that the fluorimetric method yielded values which were several-fold higher than those obtained with the spectrophotometric method when sera from pregnant women were tested. The fluorescence from sera of pregnant subjects showed a triphasic decline even when the samples were stored at --20 degrees C.