Background: Rational laboratory use is defined as effective and correct laboratory use by providing the most appropriate test selection with the right clinical approach in line with the evidence-based data and considering the cost and patient safety. The present study was thus conducted for the prevalence and features associated with rational use of investigations in a tertiary hospital. Aims and Objectives: The objectives of the study were to estimate prevalence of rational use of investigations and its associated confounding factors; to explain the educational approach underlying the study; and to explain how to teach rational approach of investigations so that we reduce the use of unnecessary and inappropriate tests which are not likely to have any ill effects on the patient. Materials and Methods: A cross-sectional study including 100 patients was selected by random sampling from medicine and orthopedic wards and OPD. Results: In our study,we observed 29 different types of clinical and laboratory investigations out of 2155 investigations ordered by physicians before any intervention. These investigations done in 100 patients, among those 39.16% were contributed to the management of patients and 60.83% were not considered to have contributed toward management of patients. Conclusion: Several external and internal factors can promote irrational use of investigation at different stages. Hence, understanding these factors and implementing appropriate measures are key steps to change behavior of prescriber and nursing staff. We must have logic-based flow chart or algorithm in all investigations for diagnosis as a part of good laboratory or good clinical practices.

Background: Hypothyroidism is a common endocrinal disorder caused by insufcient production of thyroid hormones. Subclinical hypothyroidism (SCH) can be dened as a state of high serum thyroid stimulating hormone (TSH) levels (less than 10µIU/ml) with normal serum free thyroxine (fT ) and triiodothyronine (fT ) levels in 4 3 the presence or absence of symptoms. Creatinine is a chemical waste product that is produced by muscle metabolism. Creatinine is produced from creatine, a molecule of major importance for energy production in muscles. Thyroid dysfunction can affect renal physiology and development, and on the other hand, kidney disorders can inuence thyroid function. This study was aimed to nd out the status of serum fT , fT ,TSH and serum creatinine levels in subclinical hypothyroid cases and 3 4 healthy controls. Materials and Methods: The present study is descriptive case control study, was conducted in the Department of Biochemistry, J.L.N. Medical College and Associated group of Hospitals, Ajmer (Raj.). 130 cases of subclinical hypothyroidism attending Medical OPD of J.L.N. Hospitals were included and 50 age-sex matched euthyroid controls were selected. Results: The mean serum creatinine levels were found to be signicantly high in subclinical hypothyroid cases(0.99 + 0.19 mg%) as compared to healthy controls (0.75 + 0.15 mg%), (p<0.0001). Conclusion: Serum creatinine can be used as a biomarker for early detection of subclinical hypothyroidism in general population to prevent the morbidity and mortality which are associated with hypothyroidism. Early diagnosis and intervention of subclinical hypothyroid and their cluster of risk factor can prevent the renal dysfunction.