Conjunctival impression cytology with transfer (CICT) to detect pre-clinical vitamin A deficiency among slum children in India.

In order to establish a method usable in the field for diagnosis of pre-clinical vitamin A deficiency, conjunctival impression cytology with transfer (CICT) was used in 200 normal slum children aged 6-120 months in Chandigarh, India. Conjunctival impressions taken on cellulose acetate paper were transferred to glass slides which were fixed in ethanol and stained with alcian blue and carbol fuchsin. Sixty samples of cellulose acetate paper were preserved after transfer of impression and were stained later. Transfer was complete in forty-eight samples and in the other twelve it was incomplete. Conjunctival impressions on paper and slide of these twelve cases were comparable. At a plasma retinol concentration of < 0.70 mumol/l measured by HPLC the sensitivity, specificity and positive predictive values of CICT were 90.59%, 100% and 100% respectively. Compared with conventional conjunctival impression cytology, CICT is less time consuming, cheaper and comparable in validity. It is thus more suitable than the conventional method for mass screening.