Maternal Care addresses all the common and important problems that occur during pregnancy, labour, delivery and the puerperium. It covers: the antenatal and postnatal care of healthy women with normal pregnancies, monitoring and managing the progress of labour, specific medical problems during pregnancy, labour and the puerperium, family planning, regionalised perinatal care
Maternal Care: Skills workshop screening tests for syphilis
1. 1D
Skills workshop:
Screening tests
for syphilis
SYPHILIS RAPID TEST
Objectives
The syphilis rapid test is a specific test for
When you have completed this skills syphilis and will become positive when there
are antibodies against Treponema pallidum
workshop you should be able to:
(the organism that causes syphilis) in the
• Screen a patient for syphilis with the blood. The test result corresponds to that of
syphilis rapid test and the RPR card test. a TPHA or FTA test which are also specific
• Interpret the results of the screening tests for syphilis.
tests.
A. Equipment needed to perform
a syphilis rapid test
SYPHILIS SCREENING 1. The Abbott Determine TB Whole Blood
Essay. Each kit contains ten cards with ten
At the first antenatal visit each woman tests. The Chase Buffer (2.5 ml bottle) is
should be screened for syphilis. This could supplied with the kit.
be done at the clinic with the syphilis rapid 2. EDTA capillary tubes marked to indicate
test (Determine Syphilis TP) or RPR card 50 μl, lancets, alcohol swabs and sterile
test. If syphilis is diagnosed, the patient must gauze swabs. These are not supplied with
be informed and treatment must be started the kit.
immediately at the antenatal clinic. Positive The kit needs to be stored at room temperature
rapid screening tests must be confirmed with between 2 °C and 30 °C. Storage in a fridge is
a laboratory RPR or VDRL test. The syphilis required during summer time. The kit must
rapid test or RPR card test can be used in not be used after the expiry date.
any antenatal clinic, as no sophisticated
equipment is required.
B. Performing the syphilis rapid test
1. Clean the patient’s fingertip with an alcohol
swab and allow the finger to dry.
2. SK ILLS WORKSHOP : SCREENING TESTS FOR SYPHILIS 55
2. Remove a test strip from the foil cover. 2. A negative test indicates that a person
3. Prick the skin of the fingertip with a lancet. does not have antibodies and cannot
Wipe the first drop of blood away with a have syphilis, either in the present or
sterile gauze swab. past, unless the person was infected very
4. Collect the next drop of blood into the recently and has not yet formed antibodies.
EDTA tube. Either side of the tube can be
used to collect blood. Fill the tube from the E. Management if the syphilis
tip to the first black circle (i.e. 50 μl blood). rapid test is positive
Avoid the collection of air bubbles.
5. Apply the 50 μl of blood from the EDTA 1. Explain to the patient that the screening
tube onto the sample pad marked with an test for syphilis is positive but that this
arrow on the test strip. should be confirmed or rejected by a
6. Wait until all the blood has been absorbed laboratory test (RPR or VDRL test).
into the sample pad and then apply one 2. It is advisable, however, that treatment with
drop of Chase Buffer. The bottle must penicillin be started immediately so that
be held vertically (upside down) above the fetus can be treated while waiting for
the test strip when a drop of the buffer is the result of the laboratory test.
dropped onto the sample pad. 3. Ask the patient to return in one week for
7. Wait a minimum of 15 minutes and then the result of the laboratory test.
read the result. The maximum waiting time
for reading the test is 24 hours. After 24 F. Interpretation of the RPR or VDRL test
hours the test becomes invalid. when the syphilis rapid test is positive
1. If the RPR or VDRL is negative the patient
C. Reading the results of the does not have syphilis. Treatment can be
syphilis rapid test stopped.
1. Positive 2. If the RPR or VDRL titre is 1:16 or higher
A red bar will appear within both the the patient has syphilis and must be
Control window and the Patient window treated with a full course of three doses
on the test strip. Any visible red bar in of benzathine penicillin (Bicillin LA of
the Patient window must be regarded as Penilente LA).
positive. 3. If the RPR of VDRL titre is 1:8 or lower
2. Negative and the patient and her partner have been
A red bar will appear within the Control fully treated in the past three months,
window but no red bar is seen in the treatment can be stopped. Otherwise, a
Patient window. full course of three doses of benzathine
3. Invalid penicillin must be given.
If no red bar appears in the Control
window, even if a red bar is visible in the
Patient window, the result is invalid and THE RPR CARD TEST
the test must be repeated.
The RPR card test is a non-specific test that
D. The interpretation of the will become positive if the patient has syphilis.
syphilis rapid test The result corresponds to that of a laboratory
1. A positive test indicates that a person has RPR and VDRL test which are also non-
antibodies against syphilis. This means that specific tests for syphilis.
the person either has active (untreated)
syphilis or was infected in the past and no
longer has the disease.
3. 56 MATERNAL CARE
G. Collecting a blood sample tested at the same time, the test tube of
clotted blood must be numbered and the
A 3 ml sample of venous blood is needed
same number must be written on the card
for the test. Place the blood in a test tube for
with a soft pen. Make sure that the number
clotted blood (red-topped tube).
on the test tube always corresponds to the
number on the card.
H. Equipment needed to 5. Using the flat end of the stirrer, spread the
perform a RPR card test drop of serum over the whole area within
1. The carbon antigen suspension. the circle.
2. The antigen dispenser attached to the 6. Shake the antigen dispenser containing the
special calibrated needle with a blunt tip. antigen suspension well. Use the dispenser
3. The special stirrers (Dispenstirs). with the attached calibrated needle to place
4. The white RPR card. one drop (50 μl) of antigen onto the serum
5. The test tube holder. in the circle.
7. The card must now be gently rocked by
Except for the test tube holder, all the necessary hand so that the serum and the antigen
equipment comes with the RPR card kit. suspension are well mixed, while the fluid
If many tests are to be done each day and the on the card remains within the circle. If
container with the carbon antigen will be used available, an electrical rotator can be used
up within three weeks, it is not necessary to to rock the card.
keep the container in a fridge. However, the 8. After four minutes of hand rocking or
container should be kept in a fridge if it is to eight minutes of electronic rocking the test
be used for more than three weeks. can be read.
NOTE A number of different commercial J. Reading the results of the RPR card test
companies manufacture RPR card tests. (A RPR kit
can be obtained from Davies Diagnostics at the 1. A positive test
toll free number 0800 110 509 in South Africa). Obvious clumping takes place
(flocculation). Definite black particles form
I. The method of performing which are clearly seen with the naked eye.
the RPR card test While the particles cover the whole area of
the spread-out droplet, they tend to gather
1. Keep the test tube containing 3 ml of around the edge of the droplet.
clotted blood in an upright position. It is 2. A negative test
important to remove the stopper when the No clumping takes place. The small black
blood is placed in the tube. particles of the carbon antigen tend to
2. Place the test tube in the test tube stand collect at the centre of the spread-out
for 30 minutes so that the serum can be droplet where they form a black dot.
expressed from the clotted blood. They do not collect around the rim of the
3. Use the special stirrer to transfer one drop droplet as is seen in a positive test.
of serum from the test tube to the card.
Squeeze the hollow stirrer between your K. Interpretation of the results
thumb and forefinger while the tip of the of the RPR card test
stirrer is in the serum. Now relax your
1. A positive test
grip on the stirrer and a sample will be
Explain to the patient that the screening
sucked up.
test for syphilis is positive, but that this
4. Place the tip of the stirrer above the test
should be confirmed or rejected by a
card and again squeeze the stirrer so that
laboratory test. It is advisable, however,
one drop falls onto the centre of the circle.
that treatment with penicillin be started
If the serum of more than one patient is
4. SK ILLS WORKSHOP : SCREENING TESTS FOR SYPHILIS 57
Edge of droplet clearly outlined Edge of droplet not clearly outlined
POSITIVE NEGATIVE
Figure 1D-1: Examples of positive and negative tests
immediately so that the fetus can be NOTE It is advisable that one out of every
treated. If possible, send a sample of clotted 20 negative RPR tests be checked with
blood to the laboratory for a RPR or VDRL a laboratory VDRL test in order that
test and ask the patient to return in one quality control can be observed.
week for the result. If it cannot be decided whether clumping of
particles is present or not, a sample of the
NOTE When the RPR card test is clearly positive the
patient’s blood must be sent to the laboratory
laboratory RPR or VDRL is almost always positive
for a VDRL test. The patient must be seen
with a titre of 1:8 or more. If the laboratory RPR
or VDRL is negative, the patient does not have
again as soon as the results are available and
syphilis and the treatment can be stopped. treatment given according to the laboratory
results. If the patient cannot come back for the
2. A negative test result or if it is not possible to get a laboratory
The patient can be reassured that she does VDRL, start treatment immediately.
not have syphilis. No treatment is needed.