Indian J Med Res 131, March 2010, pp 445-448
Utility of pH test & Whiff test in syndromic approach of abnormal
vaginal discharge
Jyoti Thulkar, Alka Kriplani & Nutan Agarwal
Department of Obstetrics & Gynecology, All India Institute of Medical Sciences, New Delhi, India
Received September 18, 2008
Background & objective: In India, National AIDS Control Organization (NACO) introduced syndromic
approach to treat patients with abnormal vaginal discharge without a need for laboratory tests. Simple
tools like pH test and Whiff test can be done without high expertise, microscope and even speculum. This
can improve diagnostic value of syndromic approach of abnormal vaginal discharge. The present study
was conducted to evaluate sensitivity and specificity of pH test and Whiff test in diagnosis of abnormal
vaginal discharge, considering microscopic diagnosis as gold standard.
Methods: This prospective hospital-based study included 564 women with abnormal vaginal discharge.
All women were subjected to gynaecological examination, pH test and Whiff test. The findings were
compared with microscopic examination. Statistical analysis was done by calculating proportions,
percentage, sensitivity and specificity.
Results: Vaginitis was diagnosed in 301 (53.37%) women. Bacterial vaginosis (BV) was the commonest type
of vaginitis (39.01%). Cervical erosion was the second most common cause (17.91%) and physiological
discharge was the third (14.36%). pH > 4.5 and positive Whiff test had sensitivity of 94.09 per cent and
specificity 87.5 per cent in diagnosing BV. Similarly pH < 4.5 and positive or negative Whiff test had
sensitivity of 83.72 per cent in diagnosing candidiasis.
Interpretation &conclusion: pH test and Whiff test can improve diagnostic value of speculum examination
where microscope facilities are not available.
Key words Bacterial vaginosis - pH test - syndromic approach - vaginal discharge - Whiff test
Reproductive tract infections (RTI), including
sexually transmitted infections (STI) have been
recognized as a major public health problem in India
after introduction of Reproductive and Child health
(RCH) programme in October 1997. National Family
Health Survey-2 reported 39.2 per cent of women in
India having one or more infections1. National AIDS
Control Organization (NACO) introduced syndromic
approach to treat patients with abnormal vaginal
discharge2. In syndromic approach, presence of white
discharge (yes/no) and type of discharge (curd like,
cervical mucopus and other abnormal discharge) is
highlighted. Many times, it is confusing to state whether
it is abnormal discharge or normal physiological
discharge. In this situation if vaginal pH test and Whiff
test are performed, definite conclusion can be drawn
445
446
INDIAN J MED RES, March 2010
and proper treatment can be given. Thus diagnostic
potential of syndromic approach is low and many times
inadequate or overuse of antibiotic is observed3.
To diagnose bacterial vaginosis (BV), Amsel’s
criteria are used worldwide4. The criteria include
four factors: (i) pH of secretion above 4.5; (ii) fishy
odour with or without addition of 10 per cent KOH
(Whiff test); (iii) homogenous, milky or creamy
vaginal discharge; and (iv) presence of clue cells on
microscopic examination.
Presence of three out of four criteria is necessary
for diagnosis of BV. In presence of abnormal vaginal
discharge, both vaginal PH and Whiff test has 100
per cent sensitivity4. Various studies have shown that
trichomoniasis grows when there is pH more than 4.5 and
candidiasis when pH is less than 4.55. By adding the first
two clinical factors of Amsel’s criteria to the syndromic
approach, four groups are formed: group I: pH > 4.5 &
positive Whiff test, group II: pH > 4.5 & negative Whiff
test, group III: pH < 4. 5 & positive Whiff test and group
IV: pH < 4.5 & negative Whiff test.
Gutman et al6 have mentioned that pH test and
Whiff test are sufficient to diagnose BV, but nobody
has studied its application in syndromic approach for
abnormal vaginal discharge. Simple test like pH test
and Whiff test can be done without high expertise;
microscope and even speculum. The present prospective
study was done to assess sensitivity and specificity of
pH test and Whiff test in cases of abnormal vaginal
discharge, considering microscopic diagnosis as gold
standard.
Material & Methods
This prospective hospital based, study was done
from July 2007 to June 2008 at All India Institute of
Medical Sciences, New Delhi, India. Ethical clearance
was obtained from Institute’s ethics committee.
Consecutive 564 women with complaint of abnormal
vaginal discharge and who gave informed consent
were included in the study. Unmarried, pregnant and
post-menopausal women were excluded. All women
were subjected to gynaecological examination, pH
test and Whiff test; these findings were compared
with microscopic examination. pH test was done by
directly dipping pH strip (range 0 – 6 ) in vagina. pH
strip was colour-fixed indicator sticks, marketed by
Sigma (USA). Whiff test was done by adding 10 per
cent KOH on vaginal discharge and presence of fishy
odour was interpreted as positive test while its absence
as negative test.
Vaginal discharge was taken directly by gloved
finger from mid-vagina and three slides were made.
Two slides were used for wet mount. On one slide one
drop of saline was put and on another a drop of 10 per
cent KOH. Both slides were covered by cover-slip
and examined under microscope. Saline mount was
observed for motile flagellated pear shaped organism for
diagnosis of trichomoniasis. Candidiasis was diagnosed
by hyphe and budding yeast like structure on 10 per
cent KOH mount. Third slide was fixed with ethanol
and send for Nugent’s scoring. Bacterial vaginosis was
diagnosed by Nugent’s criteria7. Nugent’s score 7-10
was considered diagnostic of BV. Mixed vaginitis was
diagnosed when more than one organism was found in
above mentioned tests.
Physiological discharge was considered when pH
was less than 4.5 and/or no above mentioned cause
was found. Cervicitis was diagnosed when there was
cervical muco-pus, on clinical examination. Special
laboratory investigation for Chlamydia and gonorrhoea
were not done. Pelvic inflammatory disease (PID) was
diagnosed by clinical examination, as laboratory tests
are expensive and specificity is low. Pap smear was
taken in cases of cervical lesion to rule out cancer.
Depending on results of pH test and Whiff test, patients
were divided into 4 groups.
Group I:
women.
pH > 4.5 & positive Whiff test – 250
Group II: pH > 4.5 & negative Whiff test – 198
women.
Group III: pH < 4.5 & positive Whiff test – 68
women.
Group IV: pH < 4.5 & negative Whiff test – 48
women.
Statistical analysis was done by calculating
proportions and percentages. Sensitivity and specificity
of pH test and Whiff test was calculated, considering
microscopic diagnosis as gold standard.
Results
Detailed analysis of all women showed mean
age of 29.9 ± 4.2 yr (range 18-42 yr). Vaginitis was
diagnosed in 301 of 564 (53.37%) women. Of these
301 cases of vaginitis, 10 had cervical erosion, 4 had
cervicitis and 3 had PID along with vaginitis. BV was
the commonest type of vaginitis (39.01%). Cervical
erosion was the second most common cause (17.91%)
and physiological discharge was third (14.36%;
Thulkar et al: Utility of pH test & Whiff test
Table I). Bacterial vaginosis was the most common
cause of vaginal discharge in groups I and II (Table II).
Candidiasis was the common cause in groups III and
IV and trichomonal vaginitis in groups I and II (Table
II). Physiological discharge did not show any specific
pattern but was absent in group I.
Discussion
Our findings revealed that BV was the commonest
cause of abnormal vaginal discharge and this could
be missed by only speculum examination. An
epidemiological survey conducted in Delhi reported BV in
32.8 per cent of women8. According to NACO guidelines
bacterial vaginosis requires treatment with metronidazole
(500mg) twice daily for 7 days without a need of
combination of antibiotics2. Of the 301 cases of vaginitis,
only 7 cases (4 cervicitis and 3 PID) had upper RTI,
which required treatment of gonorrhoea and Chlamydia
trachomatis. Other common causes were cervical erosion
and physiological, which is normal phenomenon of
body and does not require antibiotic treatment. If proper
Table I. Causes of abnormal vaginal discharge depending on
speculum and microscopic examination
Type of
vaginal
smear
Normal
Vaginitis*
Cause of discharge
Physiological
Cervical erosion
Cervicitis
PID
Bacterial vaginosis
Candidiasis
Trichomonal vaginitis
Total
Number (%) of
women
081 (14.36)
101 (17.91)
060 (10.64)
021 (03.72)
220 (39.01)
043 (07.62)
038 (06.74)
564 (100)
10 had cervical erosion, 4 had cervicitis and 3 had pelvic
inflammatory diseases (PID) along with vaginitis.
*
7 cases of bacterial vaginosis had trichomoniasis as well but they
were categorized under bacterial vaginosis
*
447
gynaecological examination, pH test and Whiff test are
done; overuse of antibiotic can be avoided.
With pH > 4.5 and positive Whiff test (group I);
BV was the commonest cause of abnormal vaginal
discharge. In the present study with pH >4.5 and
positive Whiff test had sensitivity of 94.09 per cent,
specificity 87.5 per cent, positive predictive value
(PPV) of 82.8 per cent and negative predictive value
(NPV) of 95.86 per cent in diagnosing BV (Table III). In
a study by Chaijareenont et al4, both pH and Whiff test
demonstrated 100 per cent sensitivity. Therefore doing
pH test and Whiff test will be useful in diagnosing BV
where microscope facilities are not available.
Only single criterion as pH >4.5, had sensitivity
100 per cent, specificity 33.72 per cent, PPV 49.11 per
cent and NPV 100 per cent while only Whiff test has
sensitivity 94.09 per cent, specificity 67.73 per cent,PPV
65.09 per cent and NPV 94.72 per cent in diagnosing
BV. This shows that vaginal pH is the most sensitive
single criterion in diagnosis of bacterial vaginosis.
Similar findings have been reported earlier9,10.
Candidiasis (36/43 i.e., 83.72%) was the commonest
infection when pH was less than 4.5 and negative or
positive Whiff test (groups III & IV). In our study, pH
< 4.5 and negative or positive Whiff test had sensitivity
of 83.72 per cent, specificity 84.64 per cent, positive
predictive value 31.03 per cent and negative predictive
value 98.44 per cent for candidiasis. An earlier study
also showed that risk of Candidiasis was increased
when vaginal pH was below 4.511. According to NACO
guidelines, Clotramazole vaginal pessary (200 mg) for 3
nights or oral fluconazole (150 mg) once is required2.
Trichomonal vaginitis was found in groups I and II
(52.63 and 47.37% respectively). pH >4.5 and positive
or negative Whiff test had sensitivity of 100 per cent,
specificity 22.05 per cent, positive predictive value 8.48
Table II. Cause of discharge and group-wise analysis
Cause of discharge
Bacterial vaginosis
Candidiasis
Trichomonal vaginitis
Physiological
Cervical erosion
Cervicitis
PID
Total
PID, pelvic inflammatory disease
Group I
N(%)
207 (94.09)
7 (16.28)
20 (52.63)
0
0
3 (5)
13 (61.90)
250
Group II
N(%)
13 (05.91)
0
18 (47.37)
38 (46.91)
72 (71.29)
51 (85)
6 (28.57)
198
Group III
N(%)
0
13 (30.23)
0
26 (32.10)
21 (20.79)
6 (10)
2 (09.52)
68
Group IV
N(%)
0
23 (53.49)
0
17 (20.99)
8 (07.92)
0
0
48
Total
220
43
38
81
101
60
21
564
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INDIAN J MED RES, March 2010
Table III. pH > 4.5 and positive Whiff test for bacterial vaginosis
pH > 4. 5 and
positive Whiff test
Result: positive
Result: negative
Total
Microscopic diagnosis for
bacterial vaginosis
positive
negative
207
43
13
301
220
344
Total
250
314
564
per cent and negative predictive value of 100 per cent
in diagnosis of trichomonal vaginitis. Plourd5 reported
that pH > 4.5 was present in 70 per cent of patients with
trichomonal vaginitis. According to NACO guidelines,
it responds well to metronidazole treatment for 7 days
and male partner treatment is also required.
Physiological discharge did not show any specific
pattern and does not require antibiotic treatment.
Cervical erosion, cervicitis and PID should be
diagnosed by complete gynaecological examination;
pH test and Whiff test has no role in diagnosis.
Advantage of doing pH test and Whiff test is that it
requires less training and can be done without speculum,
and antibiotic use can be restricted. But compared to
speculum examination, it will not diagnose condition
like cervicitis, cervical erosion and PID. Results of pH
test and Whiff test are comparable to microscopy and
these tests are cost-effective and less time consuming
as compared to microscopy. Lascar et al9 reported the
same. Based on these results, incorporation of pH test
and Whiff test is suggested in syndromic approach of
vaginal discharge (Fig.).
To conclude, treatment with metronidazole tablet
is required in groups I and II women and clotramazole
treatment is required in groups III and IV women. Thus
antibiotic use can be restricted by doing these two simple
tests and diagnostic value of speculum examination
can be improved where microscope facilities are not
available.
References
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1999.
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Government of India, Ministry of Health and Family Welfare.
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Aggarwal AK, Kumar R. Syndromic management of vaginal
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Plourd DM. Practical guide to diagnosing and treating
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Bhalla P, Chawla R, Garg S, Singh MM, Raina U, Bhalla R, et
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Fig. Suggested modification to treat abnormal vaginal discharge
(without speculum).
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Reprint requests:Dr Jyoti Thulkar, E-89 Ansari Nagar (east), New Delhi 110 029, India
e-mail: jthulkar@gmail.com