Conjunctival impression cytology with transfer in the assessment of vitamin A status in Nigerian children.

OBJECTIVE

To determine vitamin A status by conjunctival impression cytology with transfer (CIC-T) and assess its ability to predict low and deficient serum retinol concentrations.

STUDY DESIGN

CIC-T was performed on 128 healthy, well-nourished and 230 malnourished children aged under 6 years by a 3-5-second application of cellulose acetate paper to each bulbar conjunctiva followed by transfer of the adhered cells onto glass slides. The slides were stained with Alcian green 2GX, and smears were classified as normal, borderline normal, borderline abnormal and deficient. Corresponding serum retinol levels were determined in each subject.

RESULTS

The results showed that CIC-T is a simple procedure with a failure rate of 7.3% caused by tearing and agitation. The power of CIC-T to predict vitamin A status varied with both the CIC-T smear classification used and serum retinol concentration threshold. CIC-T smear classification as abnormal and normal appears to be the most robust and predictive of serum retinol, < 10 and > 10 < 20 micrograms/dL, respectively.

CONCLUSION

The simplicity, sensitivity and specificity of CIC-T suggest that this procedure is a good screening tool for epidemiologic survey of vitamin A status.