The correlation between liver vitamin A concentrations in micro- (needle biopsy) and macrosamples of human liver...

A technique is described for the analysis by gradient-elution reverse-phase high-pressure liquid chromatography of vitamin A at 325 nm in small liver samples taken by needle biopsy. This assay, in contrast to previous procedures, allows rapid separation and quantitation of approximately 0.1 microgram retinol and retinyl esters, requires only 7 mg liver sample, and separates groups of retinyl esters. Vitamin A values determined in needle biopsy samples (7 to 70 mg) and in gross samples (1 to 6.3 g) of the same 24 autopsy specimens correlated well (R = 0.96) over the range 1 to 400 micrograms vitamin A per g liver. The ratio of total vitamin A values in micro- and macrosamples was 1.09 +/- 0.46 (SD). Total vitamin A values in macrosamples of liver determined by high-pressure liquid chromatography and by a differential spectrophotometric assay also correlated well (R = 0.91). Under suitable clinical conditions, the procedure should be useful in validating indirect techniques for assessing vitamin A status.