Nugent Scoring System for Gram-stained Vaginal Smears (Scoring System of the Vaginal Infection and Prematurity Study Group)

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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Description

Specialty

ICD-10