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Description

Nugent et al developed a standardized method for reading Gram stains of vaginal smears. This can help evaluate the vaginal microflora and is useful in the diagnosis of bacterial vaginosis.


 

Method:

(1) A smear of vaginal fluid is Gram stained and then examined microscopically.

(2) Key organisms identified and graded on smear:

(2a) Lactobacillus morphotype

(2b) Gardnerella and Bacteroides species

(2c) Mobiluncus morphotype (curved, Gram-variable rods)

Number of Each Morphotype Seen Per Oil Field

Grading

none of morphotype

0

< 1

+1

1 – 4

+2

5 – 29

+3

30+

+4

 

 

Parameter

Grading

Points

Lactobacillus morphotypes

4+

0

 

3+

1

 

2+

2

 

1+

3

 

0

4

Gardnerella and Bacteroides species morphotypes

0

4

 

1+

3

 

2+

2

 

3+

1

 

4+

0

curved gram-variable rods (Mobiluncus species)

0

0

 

1+

1

 

2+

1

 

3+

2

 

4+

2

 

score =

= SUM(points for the 3 parameters)

 

Interpretation:

• minimum score: 0

• maximum score: 10

 

Nugent Score

Interpretation

0 – 3

normal flora

4 – 6

disturbed flora

7 - 10

bacterial vaginosis

 

Reported performance relative to clinical signs: sensitivity 86%, specificity 87-96%

 


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