Is leucocyte ascorbic acid an unreliable estimate of vitamin C deficiency?

Leucocyte ascorbic acid levels failed to identify six of seven elderly patients shown to be deficient on an oral vitamin C saturation test. Compared to those with a normal saturation test, patients judged deficient had lower levels for triceps skinfold thickness, mean arm muscle circumference and Quetelet's index; there was a significant association with the habit of eating alone, and with a dietary intake of less than 30 mg of ascorbic acid daily (the recommended daily allowance in the U.K.). No significant difference was found in the values for haemoglobin, serum albumin or potassium concentrations between the two groups, and no association shown between a deficient saturation test and smoking, season, sublingual varicosities or an abnormal bleeding time.