The diagnosis of neonatal infection is challenging because traditional markers of infection are often misleading instead of diagnosing. This study was conducted to determine Procalcitonin (PCT) level as an early marker for diagnosis of suspected sepsis in neonates in comparison with C-reactive protein, blood culture, total and differential white blood cell counts. From August, 2008 till March, 2009, 114 blood samples were collected from neonates (males and females) admitted to the pediatricsneonatal wards at Tikrit Teaching Hospital who were clinically suspected with sepsis as diagnosed by the physician in the hospital with any features suggestive of sepsis. The results of blood culture showed that 53 (46%) of samples were positive, of them 32 (60%) were males and 21 (40%) were females. The number of negative cases were 61 (54%), of them 31 (51%) were females and 30 (49%)were males. The results of identification showed that the most frequent bacterial isolates were Coagulase Negative Staphylococci and Nocardia spp. (22% for each), followed by Listeria monocytogenes 17%, Klebsiella pneumoniae, 9% Pseudomonas aeruginosa 6% and Staphylococcus aureus 6%, while (Citrobacter diversus, Serratia marscesens, Serratia liquifascens, Lactobacillus spp., Peptostreptococcus spp., Micrococcus spp., Streptococcus pyogenes) were frequently less isolated recording 2% for each . The antibiotics susceptibility test revealed that Gram negative isolates showed high resistance to antibiotics used in the present study. Each isolate of the Gram positive bacteria showed different pattern of resistance against the antibiotics used. Results of virulence factor showed that 85%, 100%, 100% , 100% and 62% of Gram negative isolates and 61%, 100% , 89%, 94% and 78% of Gram positive isolated produced Urease , Hemolysin, Lipase, Lecithinase and alkaline protease, respectively. Results of routine hematological tests at which the differences were statistically significant showed that 33% of culture positive cases had leucopenia, 19% of cases had leukocytosis, while the rest were in the category of normal range. For CRP, the differences were not significant among culture positive and culture negative cases. With reference to PCT test which had been measured using the immunochromatographic semi-quantitative method. The results showed that 21% of culture positive cases were with PCT level with high levels distributed among levels of PCT≥0.5 ≥2 ≥10 ng/ml. As for culture negative cases, 49% of PCT were systemic infections cannot be excluded though they were culture negative. In addition PCT results did not fit with CRP all the time since some cases recorded higher level of PCT ≥10 ng/ml despite they were negative for CRP. The comparison between results of PCT and WBC for the same performed cases showed that 68% of cases were in the category of normal WBC range, meanwhile they had high level of PCT. Only 18% were in the category of leukocytosis, and the rest of percentage were in the category of leucopenia. When PCT was compared with other routinely measured parameters used in this study, It seemed to be significantly more sensitive in sepsis diagnosis. Accordingly, we can conclude that PCT is a more sensitive marker than other traditional tests (blood culture, CRP and WBC count) that could be used in early diagnosis of bacterial sepsis in neonate
