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%
Specialty: Infectious Diseases, Obstetrics & Gynecology
ICD-10: ,