Background: Right heart catheterization is the gold standard in PH diagnosis, however it is invasive, costly and needs the experts so not all hospitals can carry out it. Therefore, an alternative diagnostic methods is required. Aim: to assess accuracy of Preliminary Methods in Diagnosis of pulmonary hypertension patients. Patients and methods: This cross-sectional study was carried out in Chest and cardiology departments at Zagazig University Hospitals on thirty moderate and severe PH patients during the period from July 2023 to February 2024. All patients were subjected to full history and clinical examination, laboratory investigations, ECG, Imaging techniques, trans thoracic Echocardiography, 6-minute walk distance test, Spirometric pulmonary function test and all patients also subjected RHC. Results: The mean age of studied patients was 41.5±19.1 and range of age (18-65) years. 63.4% were females. Spirometric pulmonary function FEV1% and FVC% were significantly decreased in cases with severe PH compared to moderate PH patients. Right heart catheterization data analysis that Mean PAP was Severely elevated in (93.3%) of patients, PVR was high in 76.6%. Echocardiography showed sensitivity 82.1%, specificity 50% and accuracy 80% to discriminate severe PH . congenital heart diseases were the highest percent among the causes of PH in the studied patients 46.6% and only one case was Idiopathic PH 3.3%, PH patients with lung diseaes were 4 (13.3%). Conclusion: Echocardiography shows high sensitivity (82.1%) and accuracy (80%) to discriminate severe PH . Significant decrease in spirometric pulmonary function test (FEV1, FVC) values in severe compared to moderate pulmonary hypertension patients.