ABSTRACT
Objective: to evaluate a novel clinico-biochemical score for screening of inherited metabolic diseases [IMDs] in children in our setup
Study Design: descriptive analytical study
Place and Duration of Study: department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology, Rawalpindi, from August 2016 to August 2017
Methodology: clinical data, preliminary biochemical investigations, plasma amino acid [PAA] and organic acid profiles [where indicated] of 354 children, aged <1 year to 12 years, referred to the study place for evaluation of suspected inherited metabolic diseases, was collected and evaluated. A clinico-biochemical score card named Rawalpindi Inherited Metabolic Diseases Score [RISc] was devised, on a scale from 1 to 10, incorporating 5 clinical and 5 important biochemical findings, and each variable was assigned a score, based on its relative frequency/risk. Each case was then assigned the RISc score and evaluated for presence or absence of any inherited metabolic disease, based on the score. This score was validated keeping plasma amino acids and organic acid profiles [in selected cases] as reference standard
Results: patients were divided into three groups, based on RISc score as low RISc [0.5-2.5], medium RISc [3.0-5.5] and high RISc [6-10]. A total of 354 cases reported in 2016 and 2017 and 33 [9.3%] were diagnosed to be having IMDs. One [3.0%] patient from low RISc, four [12.1%] from medium RISc, and 28 [84.8%] from high RISc group were found to test positive for any one IMD. High RISc group had a statistically significant higher IMD rate than the other two groups [p<0.001]. Specificity, sensitivity, positive likelihood ratio, negative likelihood ratio, positive predictive value, negative predictive value and accuracy were 93%, 85%, 11.8, 0.16, 55%, 98% and 90%, respectively
Conclusion: the cost effective RISc, based on clinical data and preliminary biochemical investigations, is highly accurate in diagnosing IMDs in cost restrained setups. It is strongly suggested that the initial screening for suspected IMDs and decision for advanced laboratory testing be carried out, based on the RISc card presented in the study