Role of hematological parameters in predicting retinopathy of prematurity (ROP) in preterm neonates

To study the role of hematological parameters in predicting retinopathy of prematurity (ROP) in preterm neonates.

Two hundred forty eight babies less than 34 wk and/or with a birth weight of less than 2,000 g were evaluated. Peripheral blood smear and complete blood count were done on day one of life. Ophthalmological examination was done as per guidelines and grades of ROP classified and followed up till 40 wk of gestation for complete vascularisation. Cases were matched with similar number of controls (n = 67) and the sensitivity, specificity and positive predictive value of different parameters were assessed.

The incidence of ROP on screening was found to be 27%. Sixty seven cases were matched with 67 controls as per birth weight and gestational age. Significant risk factors for ROP included longer duration of ventilation, higher FiO2, culture proven sepsis and apnea requiring pharmacotherapy. The incidence of Stage I was 10.5% (n = 7), Stage II 58.2% (n = 39) and Stage III was 31.3% (n = 21). The absolute nucleated RBC (ANRBC) count was found to be the only parameter which was significantly higher in babies with ROP (p < 0.001). The ANRBC was higher with increasing severity of ROP (p = 0.003). The sensitivity, specificity and positive predictive value of ANRBC with ROP was higher than other parameters.

Increase in ANRBC count correlated with intrauterine hypoxia. Hence, an increase in ANRBC count could be used as a screening tool for the early prediction of ROP in babies.