Significance of Hematological Scoring System (HSS) in Early Diagnosis of Neonatal Sepsis
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- Narasimha, A. & Harendra Kumar, M.L. Indian J Hematol Blood Transfus (2011) 27: 14. doi:10.1007/s12288-010-0050-2
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Neonates are easily prone for bacterial infection. Diagnosis of neonatal septicemia may be difficult as the early signs of sepsis may be subtle and different at different gestational ages. The present study was undertaken to assess the significance of the hematological scoring system (HSS) for early detection of neonatal sepsis. About 50 peripheral blood smears of all newborns collected were analysed for neonatal sepsis using the HSS of Rodwell et al. (J Pediatr 112:761–767, 1988). Analysis in our study found that an abnormal immature to total neutrophil ratio (I:T) followed by an abnormal immature to mature neutrophil ratio (I:M) were the most sensitive indicators in identifying infants with sepsis. The HSS is a simple, quick, cost effective tool which can be used as a screening test for early diagnosis of neonatal sepsis.
KeywordsHematological scoring systemNeonatal sepsisPeripheral blood smearsInfections
Early diagnosis of neonatal septicemia is a vexing problem because of its nonspecific clinical picture . Bacterial infection in the newborn still account for a considerable morbidity and mortality. This is because the newborn especially the premature are prone to serious infections by organisms and partly because the signs of these infections may be absent or minimal and hard to detect. Thus fatal septicemia may occur with little warning . Hence the timely diagnosis of sepsis in neonates is critical as the illness can be rapidly progressive and in some instances fatal .
The current study was undertaken to assess the significance of the hematological scoring system (HSS) for early detection of neonatal sepsis.
Materials and Methods
The present study is a prospective analysis of the hematologic profiles of 50 neonates admitted in the neonatal care unit of our hospital. Infants were enrolled in the study if there were predisposing perinatal factors or if there was clinical suspicion of sepsis.
The study included three groups:
Group 1—infants with sepsis with positive blood cultures. Group 2—infants with probable infection with strong clinical history but negative blood cultures. Group 3—normal infants without any evidence of sepsis. The blood samples were collected in non-siliconized Vaccutainer tubes with tripotassium EDTA as an anticoagulant. Peripheral blood smears were be prepared within 1–2 h of venipuncture, stained with Leishman stain and examined under oil immersion light microscopy at a final magnification of ×1000. The sepsis work up included blood and CSF culture and routine blood counts along with the hematologic score. Total leucocyte count was obtained using micros 60 autoanalyzer and corrected for nucleated red blood cells. Differential counts were performed on Leishman stained smears and about 200 cells were counted.
Hematological scoring system
Total WBC count
≥25,000 at birth
≥21,000—Day 2 onwards
Total PMN count
No mature PMN seen
Immature PMN count
I:T PMN ratio
I:M PMN ratio
Degenerative changes in PMN
Toxic granules/cytoplasmic vacuoles
White blood cell and platelet count
White blood differential count
Nucleated red blood cell count (to correct WBC count)
Assessment of neutrophil morphology for degenerative changes
Interpretation of hematological scoring system
Sepsis is unlikely
3 or 4
Sepsis is possible
Sepsis or infection is very likely
To test the statistical significance of three different groups, we employed the Kruskal Willis non-parametric test and a P value < 0.05 was considered as significant.
Group distribution of cases
Number of cases (%)
Group 2—probable infection
Group 3—Normal infants
The diagnosis of sepsis was made when there were positive findings on blood culture. Infant were classified as having probable infection when the blood culture was negative but there was a strong clinical history for infection. Infants were considered to be normal when the blood culture was negative and there was no strong clinical evidence of infection.
Age and sex distribution of cases
0–24 h (D1)
24–48 h (D2)
48–72 h (D3)
72–96 h (D4)
Scores of each of the groups
Score 0–2 (%)
Score 3–4 (%)
Score ≥ 5 (%)
Sepsis (12 cases)
Probable infection (26 cases)
Normal (12 cases)
Performance of individual hematologic findings
Positive predictive value (PPV) (%)
Negative predictive value (NPV) (%)
Total WBC count
Total PMN count
I PMN count
I:T PMN ratio
I:M PMN ratio
Neonatal sepsis, sepsis neonatorum, and neonatal septicemia are terms that have been used to describe the systemic response to infection in newborn infants. Sepsis in newborn can be a devastating problem leading to morbidity and mortality. The inability of neonates to completely muster the minimum inflammatory response makes them more susceptible to bacterial invasion of the blood stream than older children and adults and the risks are even higher in preterm infants. Diagnosis of neonatal septicemia may be difficult as the early signs of sepsis may be subtle and different at different gestational ages .
Inability to adequately exclude the diagnosis of neonatal sepsis can result in unnecessary and prolonged exposure to antibiotics. Thus laboratory tests that assist the clinician in diagnosis of infection in neonates have considerable relevance .
In our study considering all four parameters i.e: sensitivity, specificity, positive predictive value and negative predictive value, I:T PMN ratio and degenerative changes were the most reliable tests for diagnosing sepsis. An abnormal I:M PMN ratio was highly sensitive in identifying sepsis. Degenerative changes in neutrophils were not found to be a very sensitive indicator of sepsis. Thrombocytopenia was consistently associated with poor prognosis. These findings were in comparison with other studies [3, 4, 7, 8]. The higher the score, the greater was the likelihood of sepsis. A score ≤2 suggests that sepsis was unlikely.
Hematologic scoring system (HSS) can improve the diagnostic accuracy of complete blood count. It can be employed as a screening test for diagnosing sepsis. But it is important to simplify and standardize the interpretation of this global test .
Though there are several methods for rapid detection of microorganisms in blood cultures of newborn infants using automated blood culture system, DNA probe and fluorometric detection systems [9–11], still HSS can be employed as a useful test to distinguish the infected from the non infected infants. It has high sensitivity and specificity, the certainty of sepsis being present with higher scores.
HSS is a simple, quick, cost effective tool which can be used as a screening test for early diagnosis of neonatal sepsis. It may aid the clinicians in identifying sepsis and to institute proper anti-biotic therapy. Unnecessary exposure of infants to antibiotic therapy can thus be avoided.
Mrs. Christina (Lab Technician) for technical help and Sri Devaraj Urs Academy of Higher Education and Research for funding.