1. Diagnosis of Leptospirosis Utilizing Modified Faine’s Criteria
Dr.S.SHIVAKUMAR, M.D., FICP., FRCP(Glasg)
Professor & HOD of Medicine(Retd)
Govt. Stanley Medical College & Hospital
Chennai

2. INTRODUCTION
Faine had evolved a criteria (WHO Guidelines) for diagnosis of Leptospirosis on the basis of clinical (A), epidemiological (B) and laboratory data (C) (A+B+C).
Certain modifications has been made on the Faine’s criteria to diagnose current leptospiral infection in Indian institutions by us in a prospective study in patients with Leptospirosis (Modified Faine’s criteria).
The modifications in the Faine’s criteria has been made in the epidemiological and laboratory criteria (Table 1)
No modifications have been made in the clinical aspects of Leptospirosis (Part A).
A score of 26 or more when using Part A, Part A+B or 25 or more using Part A+B+C can be considered as current Leptospirosis.
Dr.Shivakumar Academy

3. Modified Faine’s Criteria
Table 1
Faine’s Criteria
Modified Faine’s Criteria
Part A : Clinical Data
Question
Score
Headache 2
Fever
Temp > 39°C
Conjunctival suffusion 4
Meningism
Muscle pain
+ Meningism
+ Muscle pain 10
Jaundice 1
Albuminuria/Nitrogen
Retention
Total score
Dr.Shivakumar Academy

4. Epidemiological Factors
Table 1 (Contd…)
Part B:
Epidemiological Factors
Contact with animals or
Contact with known
Contaminated water 10
Rainfall 5
Contact with contaminated
Environment 4
Animal contact 1
Part C:
Bacteriological and Lab Findings
Isolation of leptospira in culture
– Diagnosis certain
Dr.Shivakumar Academy

5. Table 1 (Contd…) Positive Serology (MAT) Leptospirosis Endemic
Single positive – Low titre
Single positive – High titre
Leptospirosis Non Endemic
Rising titre (Paired sera)
Total Score 2 10 5 15 25
ELISA IgM Positive *
SAT – Positive
MAT – Single High titre *
Any one of the tests only should be scored
Dr.Shivakumar Academy

6. Modified Faine’s Criteria - Score Diagnosis of Leptospirosis
(Part A) or (Part A & Part B Score) : 26 or more
Part A, B & C (Total) : 25 or more 6
Dr.Shivakumar Academy

7. REASONS BEHIND MODIFICATIONS
Most of the cases of Leptospirosis are reported in the monsoon and post Monsoon seasons.
Factors such as rainfall and contact with contaminated environment have been incorporated with appropriate scores (Part B).
Laboratory tests are very essential for diagnosis of Leptospirosis. Important modifications have been made in the laboratory criteria by introducing simple diagnostic tests.
Dr.Shivakumar Academy

8. REASONS BEHIND MODIFICATIONS (Contd…)
ELISA IgM and Slide agglutination tests (SAT) are simple, sensitive tests and can be used to diagnose current Leptospirosis. They have been included with appropriate scores (Part C).
Microscopic agglutination tests (MAT) is the Gold standard test, but it is complicated and less sensitive compared to ELISA and SAT
Dr.Shivakumar Academy

9. PROBLEMS IN MAT
The antibody titers rise and peak only in 2nd or 3rd week, making it a less sensitive test.
The high titers of past infection persist for a long time (1-5 years) and therefore interfere with the diagnosis of current leptospirosis.
A Positive titer may represent a rising titer of current infection or declining titer of past infection.
Dr.Shivakumar Academy

10. PROBLEMS IN MAT (Contd..)
The cut off titer for diagnosis of current infection depends in whether the area is endemic or non-endemic, E.g., the cut off titer varies from 1/80 to 1/400. Therefore a second sample is usually required (to demonstrate 4 fold rise in titer) to diagnose current infection. Sero-epidemiological studies are required for determining the cutoff value.
The test is complicated requiring dark field microscopy and cultures of various live serovars, which may not be available in small laboratories.
Dr.Shivakumar Academy

11. PROBLEMS IN MAT(Contd..)
As Elisa and SAT measures IgM antibodies become positive by 5th day, they are the tests of choice for diagnosis of current infection and more over a single sample is adequate. A repeat sample is necessary, if the first sample is negative.
High titers and rising titers of MAT have been given appropriate scores. MAT titers based on endemecity and low titers have been deleted (Part C).
Dr.Shivakumar Academy

12. AIM
This study has been undertaken to compare the standard and modified Faine’s criteria. The original Faine’s criteria (WHO guidelines) have been designated as Standard Faine’s criteria in this study.
Dr.Shivakumar Academy

13. MATERIALS AND METHODS
One hundred and fifty patients admitted with fever were taken up for the study from April 2002 to March 2003.
Leptospirosis was diagnosed by positive macroscopic slide agglutination test (confirmed by MAT). Malaria, enteric fever, UTI, pneumonia and TB was excluded by appropriate tests. Thirty-one of 150 patients (20.7%) were diagnosed to have Leptospirosis. All these patients had both standard and modified Faine’s criteria positive (A+B+C >25). It is observed that 38%(22/57) of the patients with fever had Leptospirosis during monsoon when compared to 9% in the non-monsoon season (9/93).
Dr.Shivakumar Academy

14. DISCUSSION
As Leptospirosis tests become positive only after the fifth day, the diagnosis of Leptospirosis has to be done only by clinical and epidemiological criteria during this period. Hence the clinical and epidemiological criteria (A+B) only have been compared between standard and modified Faine’s criteria (Table 2).
Dr.Shivakumar Academy

15. (PART A+B) Seropositive Seronegative
TABLE 2
(PART A+B)
Seropositive
Seronegative
Standard Faine’s Criteria
Faine’s positive
Faine’s negative
Total 13 18 31
101
119
Modified Faine’s Criteria 3
116
Dr.Shivakumar Academy

16. DISCUSSION (Contd…)
The standard Faine’s criteria had a sensitivity of 41.9%, specificity of 84.9% and a positive predictive value of 41.9%. It was observed that the positive features (A+B>26) were more in seronegative leptospirosis compared to seropositive Leptospirosis. In contrast, modified Faine’s criteria had a sensitivity of 58%, Specificity of 97.4% and positive predictive value (PPV) of 85.7%. By modifying the epidemiological factors a significantly better PPV and specificity was obtained in the modified Faine’s criteria. (Table 3).
Dr.Shivakumar Academy

17. (PART A+B) Sensit ivity Specif icity PP V NP V Standard Faine’s
Table 3
(PART A+B)
Sensit ivity
Specif icity
PP V
NP V
Standard Faine’s
Criteria
41.9%
84.9
84.9%
Modified Faine’s
58%
97.4
85.7%
89.9%
Statistical
significance NS
p.value
<0.001
Dr.Shivakumar Academy

18. DISCUSSION (Contd…)
A study conducted by AM Bal et al utilizing Faine’s criteria had observed that the sensitivity and PPV to be 81.8% and 40.9% respectively. In our study the PPV was much higher utilizing modified Faine’s criteria though the sensitivity was low. An important observation in the study has been the importance of laboratory tests.
Dr.Shivakumar Academy

19. DISCUSSION (Contd…)
If clinical and epidemiological criteria (A+B) along were utilized, only 18 cases were diagnosed by modified Faine’s criteria (sensitivity – 58%), but if lab criteria was incorporated 31 cases were diagnosed (A+B+C). This is because if A+B alone were utilized, the score should be >26, but if C is available, A+B can be just 11 (A+B=11+C=15 Total =26).
Dr.Shivakumar Academy

20. DISCUSSION (Contd…)
If lab criteria are included, the score in Part A (Clinical features) can be just 2, Part B (epidemiological factors) 9 and Part C (Laboratory test) 15 (Total = 26). Thus milder cases can be diagnosed if laboratory tests are available. In addition, the modified Faine’s criteria makes it more difficult to diagnose Leptospirosis in the non monsoon months as the epidemiological factors would be minimal (Part A=10, Part B=0, Part C=15).
Dr.Shivakumar Academy

21. DISCUSSION (Contd…)
We would like to emphasize that the study has been done in symptomatic patients only (A+B+C) to diagnose current Leptospirosis. It can be argued that a score of 25 or more can be obtained from B+C along in asymptomatic patients. This would be relevant only for epidemiological studies to evaluate the prevalence rates of Leptospirosis in high-risk group and general population.
Dr.Shivakumar Academy

22. DISCUSSION (Contd…)
This study has been done to evaluate a simple method to diagnose current leptospiral infection, with necessary modification of Faine’s criteria. Though other criteria are utilized, this criteria is most useful because it utilizes clinical, epidemiological and lab features.
Dr.Shivakumar Academy

23. CONCLUSION
To conclude, modified Faine’s criteria is a more practical method to diagnose current Leptospirosis. Availability of simple diagnostic tests (ELISA IgM or SAT) should help in diagnosis of milder forms (Anicteric) of Leptospirosis, which is more common (90%) than severe Leptospirosis (10%).
Dr.Shivakumar Academy

24. HIGH LIGHTS OF MODIFIED FAINE’S CRITERIA
No change in clinical criteria (A)
Modifications in epidemiology – Rainfall & contaminated environment were given appropriate scores (B)
3. a) MSAT and ELISA were introduced
b) Endemic and Non-endemic criteria were
removed
c) Low titres of MAT deleted
(C) 24
Dr.Shivakumar Academy

25. Reference Shivakumar S, Shareek PS
Reference Shivakumar S, Shareek PS. Diagnosis of Leptospirosis – Utilising modified Faine’s criteria. J Assoc Physicians India 2004;52:678-9
THANK YOU
Dr.Shivakumar Academy