Skip to content

Complete Blood Count (CBC) Test

Published: August 9, 2026Updated: August 16, 2026

This test checks whether a mother has received benzathine penicillin treatment, an antibiotic used to treat syphilis and prevent passing it to the baby.

Quick summary

Benzathine penicillin is an antibiotic injection used to treat syphilis in pregnant women The test confirms if the mother received proper treatment before delivery Proper treatment helps prevent congenital syphilis in newborns The test is performed on a blood sample (serum) Treatment is typically given as injections at least 3 months before delivery for best results

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
75184-2
Short code
AMOUNTOFBENZATHINEPENICILLINTREATMENT
Synonyms
—
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
cdc-cs
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

A complete blood count, also called a CBC, is a common blood test that measures the different cells in your blood, including red blood cells, white blood cells, and platelets. It gives your doctor a broad picture of your overall health and helps check for many different conditions.

The Benzathine Penicillin Treatment test checks if a pregnant mother has received benzathine penicillin, an antibiotic commonly used to treat syphilis. Syphilis is a sexually transmitted infection that can be passed from a mother to her unborn baby during pregnancy. When a pregnant woman tests positive for syphilis, she needs to be treated with benzathine penicillin injections to protect her baby from developing congenital syphilis, which can cause serious health problems.

For this test, a small sample of blood is drawn, usually from a vein in your arm. A healthcare professional will clean the site, wrap a band around your upper arm, and use a thin needle to collect the sample. The procedure takes only a few minutes, and you can usually return to your normal activities right away.

A healthcare provider will draw a small blood sample from your arm. This blood is then sent to a laboratory where it is tested to detect the presence of benzathine penicillin or its effects. The test is part of standard prenatal care when syphilis screening shows a positive result.

This test is important because it can help detect a wide range of conditions, such as anemia, infections, and blood disorders, often before you notice any symptoms. It also helps your doctor monitor ongoing health problems and see how well a treatment is working over time.

If a pregnant woman has syphilis and does not receive proper treatment, the infection can cross the placenta and infect the unborn baby. This can lead to stillbirth, premature birth, low birth weight, or serious birth defects. Treating the mother with benzathine penicillin can effectively prevent these complications. This test helps healthcare providers confirm that adequate treatment has been given.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is primarily used in prenatal care to verify treatment of syphilis in pregnant women. A positive result indicates the mother has received benzathine penicillin treatment, which significantly reduces the risk of congenital syphilis in the infant. The CDC recommends that all pregnant women be screened for syphilis early in pregnancy, with repeat testing for those at higher risk. Proper documentation of treatment is essential for preventing congenital syphilis and ensuring appropriate neonatal care.

In cases where the test shows treatment was not given or was inadequate, healthcare providers can arrange for immediate treatment. The timing of treatment is important—at least 3 months before delivery is ideal for preventing infection in the baby. This test is part of the public health effort to eliminate congenital syphilis.

Frequently asked questions

Does this test hurt?
The test involves a simple blood draw, which may cause brief discomfort or a small pinch. The procedure only takes a few minutes, and any pain usually goes away quickly.
How long does it take to get results?
Results are typically available within a few days, depending on the laboratory. Your healthcare provider will contact you with the results and discuss any necessary next steps.
What happens if I test positive for syphilis during pregnancy?
If you test positive for syphilis, your healthcare provider will give you benzathine penicillin injections to treat the infection. Treatment is safe during pregnancy and highly effective at preventing the infection from affecting your baby. It is important to complete all recommended doses.
Can I breastfeed if I was treated for syphilis?
Yes, you can breastfeed after receiving benzathine penicillin treatment. The antibiotic does not pass into breast milk in significant amounts and is safe for your baby.
Will my baby need testing after birth?
Yes, newborns whose mothers had syphilis will typically be examined and tested after birth. The baby's healthcare provider may perform blood tests and physical exams to check for signs of congenital syphilis. Early detection and treatment are important for the baby's health.
  1. 1
  2. 2
  3. 3

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy