Laboratory Test Panel: What It Is, How to Prepare, and What to Expect
A series of blood tests performed during the last three months of pregnancy to monitor maternal and fetal health.
{"Blood tests in the third trimester check for anemia, infections, and gestational diabetes","Tests include complete blood count, blood type screening, and glucose tolerance testing","These tests help ensure a healthy pregnancy and prepare for safe delivery"}
Key facts at a glance
- LOINC
- 106791-7
- Short code
- Analytical tests in the 3 trim preg
- Synonyms
- Analytical tests in the 3 trim preg
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 7
- Ref high
- 56
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84484
- SNOMED
- 302773008
- 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
This test helps your healthcare provider learn more about your health by analyzing a sample, such as blood or urine. It can be used to check how well your organs are working, look for signs of illness, or monitor a condition you already have.
Third trimester pregnancy tests are a group of blood tests performed during weeks 28 to 40 of pregnancy. These tests help your healthcare provider monitor your health and your baby's development as you near delivery. A blood sample is taken from a vein in your arm and sent to a laboratory for analysis.
The panel may include several individual measurements that are analyzed together to give your provider a more complete picture of your health. Each component looks at something different, and the combined results help guide diagnosis and treatment decisions.
The third trimester blood test panel typically includes: Complete Blood Count (CBC) to check for anemia and infection; Blood Type and Antibody Screen to determine your blood type and check for antibodies that could affect the baby; Glucose Screening to test for gestational diabetes; and Infectious Disease Screening including HIV, hepatitis B, and syphilis. Your doctor may also order additional tests based on your individual health needs.
Your provider will give you specific instructions before the test. In many cases, you may need to fast for 8 to 12 hours, drinking only water. Tell your care team about any medications, vitamins, or supplements you take, since some of these can affect your results.
For most tests, no special preparation is needed. However, for the glucose screening test, you may be asked to fast overnight or consume a specific sugary drink before the test. Follow your healthcare provider's instructions carefully. Bring your prenatal records and a list of any medications you are taking to your appointment.
If the test requires a blood sample, a trained professional will clean the site, draw a small amount of blood, and apply a bandage. The process usually takes only a few minutes. For urine tests, you will receive a container and simple instructions on how to collect the sample.
A healthcare professional will clean the inside of your elbow with an antiseptic, then insert a small needle into a vein to draw blood. You may feel a brief pinch or stinging sensation. The blood will be collected in a tube, and the needle will be removed and replaced with a small bandage. The process usually takes less than five minutes.
Reference range
Adult males: 7-56 U/L; Adult females: 7-43 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Third trimester blood tests are crucial for identifying potential complications before delivery. The CBC helps detect anemia, which is common in pregnancy and can cause fatigue and increase the risk of blood loss during delivery. Blood type screening ensures proper care if you need a transfusion and identifies Rh-negative mothers who may need Rh immunoglobulin injections to prevent complications in future pregnancies.
Glucose screening for gestational diabetes is essential because uncontrolled diabetes can lead to large birth weight, premature delivery, and increased risk of cesarean section. Infectious disease screening allows your healthcare team to take appropriate precautions to protect you and your baby during labor and delivery. Early detection and treatment of any abnormalities significantly improves outcomes for both mother and baby.
Frequently asked questions
Are these tests mandatory?
Do I need to fast before the test?
How long does it take to get results?
Are there any risks from these blood tests?
What happens if test results are abnormal?
Sources
- 1
- 2
- 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.
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 17, 2026. · Read our editorial policy