O R I G I N A L A R T I C L E S Indian J Pediatr 1993; 60 : 559-563

Evaluation of Sepsis Screen for Diagnosis of Neonatal Septicemia

Anita Sharma, C.V. Krishna Kutty, Uma Sabharwal, Sushila Rathee and Harash Mohan

Departments of Pediatrics, Microbiology, Obstetrics and Gynaecology, and Clinical Hematology, Medical College, Rohtak

Abstract. Fifty clinically suspected cases of neonatal septicemia were studied for evaluat- ing the role of sepsis screen. Sensitivity and specificity of C-reactive protein test, micro-ESR, gas- tric aspirate cytology for polymorphs and toxic granules in neutrophils were studied singly and in combinations of two and three tests. Positive blood culture was obtained in only 20% cases, thereby underlying the need for a sepsis screen in the diagnosis of neonatal septicemia, especially in areas where adequate micro-biological facilities are lacking. (Indian J Pedlatr 1993; 60 : 559-563)

Key words: Neonatal septicemia; Sepsis screen; Early diagnosis.

I ,~ India, neonatal septicemia is responsi- ble for one-fourth to nearly a half of the neonatal deaths, x The clinical diagnosis of neonatal septicemia is a difficult task. The gold standard for diagnosis of neonatal septicemia is a positive blood culture. A positive blood culture report obtained in 30-75% of cases, 24 requires a period of 48- 72 hours and in developing countries like India, the culture facilities are non-existant in most of the district hospitals. The out- come of a neonate with sepsis largely de- pends on its early identification. To meet this end several rapid diagnostic tests have been described recently. 5 Individually these tests have low sensitivity and speci- ficity, therefore a combination of these tests have been studied by many workers to formulate a reliable sepsis screen, s-8 The present study was undertaken to study the

Reprint requests : Dr.Anita Sharma, 39/9J Medical Enclave, Rohtak-124 001.

role of sepsis screen for early diagnosis of septicemia and identification of culture negative septicemic cases.

MATERIAL AND METHODS

The study group comprised of 50 clinical suspected septicemic neonates who had no obvious focus of infection.

In all the cases, at the time of admission, various investigations done were - blood culture, total leucocyte count (TLC), differ- ential leucocyte count (DLC), band count to total neutrophil ratio (B/N ratio), de- generative changes in neutrophils (Dohle body, cytoplasmic vacuolization and toxic granulations), buffy coat smear (BCS), ab- solute platelet count, micro ESR, C-reac- tive protein (CRP)- semiquantitative esti- mation by Latex .agglutination technique (Rapitex CRP test) and gastric aspirate cy- tology (GAC). The cut off values for posi- tive tests were (i) TLC <5,000/cmm or

560 THE INDIAN JOURNAL OF PEDIATRICS 1993; Vol. 60. No. 4

>20,000/cmrn, (ii) B/N ratio ___ 0.2 (iii) GAC >5 polymorphs/high power field, (iv) mi- cro ESR > 10 mm Ist hour and (iv) CRP > 6 pgm/ml. All the parameters were analy- sed singly and in combinations for their sensitivity and specificity.

RESULTS

In the present study out of 50 cases, 33 (66%) cases were more than 7 days of age, 37 (74%) were males and 35 (70%) were low birth weight (<2.5 kg). In the present study, 14 (30.8%) cases died and all of them were low birth weight babies. Neona- tal septicemia was seen in 28% preterm ba- bies. Common symptoms observed were refusal of feeds (76%), lethargy (60%) and temperature changes (52%). The most com- mon organisms isolated was Klebsiella pneumonia in 3 followed by Staphylococcus aureus in 2. Staphylococcus viridens 1, Sta- phylococcus epidermidis 1 and Pseudomonas aeruginosa in 1 case. Leucocyte count, platelet count and buffy coat smear exami- nation showed no diagnostic significance in diagnosing neonatal septicemia.

For analysis of results, study group was divided into three subgroups. Group A (n=10) was positive on culture and their clinical course was like septicemic (proved sepsis group). Group 13 (n=24) was consid- ered as probable sepsis group. This was culture negative septicemic group diag- nosed on the basis of other investigations and clinical course. Group C (n=16) was no sepsis group. This group was negative on investigations and their clinical course was also not like septicemic cases. Table 1, shows the results of individual tests. The sensitivity and specificity of individual tests (Table 2), two tests combination and three tests combination (Table 3) were

studied in group A and B, while group C served as controls.

DISCUSSION

In the present study, the blood culture was positive in only 20% cases. This was rela- tively low compared to 30-75% of positiv- ity reported by other workers. 2"4 The low positivity of blood culture underlines the need of other tests in diagnosing neonatal septicemia.

Out of the various individual tests for rapid diagnosis of neonatal septicemia, in proved sepsis group (Table 2), CRP was the one with maximum sensitivity (80%) and specificity (93.8%). Other workers have also observed similar high sensitivity (80%) and specificity (91%) with CRP. 6'9 Chandana et al 7 observed 83% sensitivity but only 42% specificity of CRP. Micro- ESR has a lower sensitivity (60%) and specificity (62%) compared to CRP in cul- ture positive (Table 2) septicemic group. Same observation was made in another re- port. 6 However, Misra et al 8 observed that m-ESR had good sensitivity and specificity both.

In the present study GAC for polymor- phs (Table 2) had high specificity (100%) but sensitivity of the test was only 67.5%. Singh et al 6 also found this test to be highly specific (81%), but with low sensitivity (38%). Chandna et al 7 found it to be a test with low sensitivity and specificity. Just like other studies, 6'7 BIN ratio in our study also had moderate sensitivity and specific- ity. This is in contrast to other reports, s's who found it to be the single most sensetive individual test.

Of the various degenerative changes ha neutrophils, in present study, toxic gran- ules were seen in 60% cases (Table 2). This

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TABLE 1. Results of Parameters Studied

561

Parameter Proven Most probable No sepsis sepsis sepsis (n=16) (n=10) (n=24)

B/N Ratio ~_ 0.2 6 16 7

(60%) (66.6%) (43.7%) <0.2 4 8 9

(40%) (33.3%) (56,3%) GA Cytology +re (>5 polys/HPF) 4 13 0

(40%) (54%) -re (<5 polys/HPF) 6 11 16

(60~ (45.8%) (10m') Toxic Granulation Present 6 18 8

(60%) (75%) (50%) Absent 4 6 8

(40%) (25%) (50%) M-ESR (ram 1st hour) > 10 6 16 6

(60%) (66.6%) (37.5%) < 10 4 8 10

(40%) (33.3%) (62.5%) CRP (l~g/ml) >6 8 15 1

(80%) (62.5%) (6.25%) <6 2 9 15

(20%) (37.5%) (93:8%)

is fairly in agreement with that reported by others, l~ However , in an another s tudy 12 toxic granules were seen in only 29% cases. Toxic granulations have been considered a Strong ev idence of sepsis by m an y workers, lt~2 but it has not been evaluated as a screening test earlier. Cytoplasmic Vacuolization were seen in 15% cases only. This is in contrast to other reports, m~ Dohle bodies were not observed in the present study, this is in contrast to that re- ported in li terature where Dohle bodies

TABLE 2. Sensitivity and Specificity of Indivi- dual Tests

Test Sensitivity Specificity (%) (~

CRP (> 6 lag/ml) 80 93.8

m-ESR (>10 mm in Ist hr) 60 62.5

Gastric aspirate 40 100 (> 5 polys/HPF) B/N ratio (>_ 0.2) 60 56.2 Toxic granulations 60 50

562 THE INDIAN JOURNAL OF PEDIATRICS 1993; Vol. 60. No. 4

were seen in 75% cases of neonatal sepsis. 12 W hen two tests combina t ions were

compared , out of several combinations CRP with any other parameter except m- ESR gave 100% sensitivity in proven sepsis g roup (Table 3). However , one cannot be carried away by 100% sensitivity of these tests because this sensitivity was to detect cul ture positive cases. In reality, the effi- ciency of a screening test for neonatal sep- ticemia should be assessed by its ability to help in early diagnosis and also to detect cul ture negative cases of sepsis as well, which was the aim of the present study. Therefore, one should give more impor- tance to the analysis of the tests in most probable sepsis group. In this group, com- bination of CRP with toxic granules had balanced sensitivity (80%) and specificity (88.9%) in present study. In general, it was

observed that specificity of the two tests combination was higher than that of indi- vidual test, but at the cost of sensitivity. Different workers found different combi- nation to be better, s-8'14 Squire et aP s how- ever, did not find a combinat ion of two or more tests particularly useful in compari- son to CRP estimation alone.

In the three test combination, in culture positive sepsis group, any test in combina- tion with CRP and m-ESR gave 100% sen- sitivity. The max imum specificity was ob- se rved for the combina t ion of CRP+m ESR+B/N ratio (Table 3). In culture nega- tive sepsis group CRP+mESR+toxic gran- ules gave maximum sensitivity (82.4%) and specificity (85.7%).

In general, three tests combination had no overall advantage over two tests combi- nation ~n present study. But this was not

TABLE 3. Sensitivity and Specificity of Combination of Tests

Combination of tests Sensitivity (%)

Proven Probable sepsis sepsis

Specificity (%)

Proven Probable sepsis sepsis

I. Two tests combinations :

CRP + m-ESR 75 70.4 54.8 91.7 CRP + gastric aspirate 100 65 66.7 100 CRP + B/N ratio 100 73.9 51.7 90 CRP + toxic granules 100 80 48 88.9 m-ESR + gastric aspirate 50 63.2 61.5 100 m-ESR + B/N ratio 66.7 70.8 42.9 70 m-ESR + toxic granules 66.7 76.2 37.5 66.7

II. Three tests combinations :

CRP + m-ESR + gastric aspirate 100 63.8 64 100 CRP + m-ESR + B/N ratio 100 75 85.7 87.5 CRP + m-ESR + Toxic gr 100 82.4 45 85.7

III. Any 2 tests or more +re 80 79.4 35 56.3

IV. A n y 3 tests or more +re 60 67.6 66.7 81.3

1993; Vol. 60. No. 4

the case when any three tests versus any two tests combinat ion was compared . For culture negative septicemic g roup whereas two tests combinat ions were more sensi- tive (79.4%), the three tests combinations were more specific (81.3%).

In the present s tudy, with the help of sepsis screen, 48% cases of culture negat ive ~epticemia could be diagnosed by sepsis screen, whereas only 20% cases were diag- nosed by posit ive culture. Tests used in the present study, can all be done in a side laboratory wi thout the help of any sophis- ticated equipment , and results are avail- able within an hour. Thir ty two percent cases, in present s tudy, were clinically sus- pected as septicemic but turned out to non-septicemic. The sepsis screen is help- ful in avoid ing overuse of antibiotics.

REFERENCES

1. Singh M, Paul VK, Deorari AK et al. Strate- gies which reduced sepsis related neonatal mortality. Indian J Pediatr 1988; 55 : 955- ~60.

2. Khatua SP, Das AK, Chatterjee BD et al. Neonatal septicemia. Indian l Pediatr 1986; 53 : 509-514.

3. Bhakoo ON. Neonatal bacterial infections at Chandigarh - A decade of experience. ludian J Pediat r 1980; 47 : 419-424.

4. Monga K, Fernandez A, Deodhar L. Changing bacteriological patterns in neonatal septicemia. Indian J Pediatr 1986; 53 : 505-508.

5. Philip AGS, Hewitt JE. Early diagnosis of neonatal sepsis. Pediatr 1980; 65 : 1036- 1041.

THE INDIAN JOU[GNAL OF PEDIATRICS 563

6. Singh M, Narang A, Bhakoo ON. Evalu- ation of a sepsis screen in the diagnosis of neonatal sepsis. Indian Pediatr 1987; 24 : 39-43.

7. Chandna A, Rao MN, Srinivas M et al. Rapid diagnostic tests in neonatal septicemia. Indian ] Pediatr 1988; 55 : 947-953.

8. Misra PK, Kumar R, Malik GK et al. Simple hematological tests for diagnosis of neonatal sepsis, indian Pediatr 1989; 26 : 156-159.

9. Squire EN. Criteria for the discontinuation of antibiotic therapy during presumptive treatment of suspected neonatal infection. Pediatr Infect Dis 1982; 1 : 85-90.

10. Haden RL. Qualitative changes in neutro- philic leucocytes. Am J Clin Patho! 1935; 5 : 354-356.

11. Xanthou M. Leucocyte blood picture in ill newborn babies. Arch Dis Child 1972; 47 : 741-743.

12. Steigbiegel RT, Johnson PK, Remington JS. The nitroblue tetrazolium reduction test versus conventional hematology in the di- agnosis of bacterial infections. N Engl J Med 1974; 290 : 235-238.

13. Zipursky A, Palko J, Milner R et al. The haematology of bacterial infections in premature infants. Pediatr 1976; 57 : 839- 841.

14. Desai N. Evaluation of laboratory parameters in early diagnosis of neonatal septicemia with special reference to C- reactive protein. Thesis AIIMS, 1984.

15. Squire I, Favara B, Todd J. Diagnosis of neonatal bacterial infections. Hematologic and pathological findings in fatal and non fatal cases. Pediatr 1976; 64 : 60-64.