What is this test?
This test evaluates blood in a newborn baby's stool or emesis (vomit). It is used to determine if the newborn baby is bleeding (fetal blood), or if the blood came from the baby's mother (maternal blood).
What are other names for this test?
- Alkaline denaturation method for fetal hemoglobin determination
- Alkaline denaturation method for foetal haemoglobin determination
Why do I need this test?
Laboratory tests may be done for many reasons. Tests are performed for routine health screenings or if a disease or toxicity is suspected. Lab tests may be used to determine if a medical condition is improving or worsening. Lab tests may also be used to measure the success or failure of a medication or treatment plan. Lab tests may be ordered for professional or legal reasons. The following are possible reasons why this test may be done:
- Perinatal gastrointestinal hemorrhage
When and how often should I have this test?
When and how often laboratory tests are done may depend on many factors. The timing of laboratory tests may rely on the results or completion of other tests, procedures, or treatments. Lab tests may be performed immediately in an emergency, or tests may be delayed as a condition is treated or monitored. A test may be suggested or become necessary when certain signs or symptoms appear.
The age or gender of the person being tested may affect when and how often a lab test is required. Chronic or progressive conditions may need ongoing monitoring through the use of lab tests. Conditions that worsen and improve may also need frequent monitoring. Certain tests may be repeated to obtain a series of results, or tests may need to be repeated to confirm or disprove results. Timing and frequency of lab tests may vary if they are performed for professional or legal reasons.
How should I get ready for the test?
Before the sample is collected, tell the healthcare worker if your newborn has a medical condition or is receiving medicine that may cause a bloody stool.
Ask the healthcare worker for information about how to prepare for this test.
How is the test done?
A sample of your newborn's stool or vomit is collected and sent to a lab for tests. A blood-stained diaper also may be used for this test.
For a stool sample collected at home, place the newborn's stool into a container provided by the healthcare worker. Collect the largest amount of stool possible for the test. Avoid getting urine, water, tissues, or toilet paper in the sample.
Methods used to obtain a sample for this test vary. Ask the healthcare worker for information about how a sample is obtained for this test.
How will the test feel?
The amount of discomfort your newborn will feel depends on many factors, including your newborn's sensitivity to pain.
What should I do after the test?
Stool or vomit should be tested within 30 minutes after it is collected, or as soon as possible.
If you collect your newborn's stool, close the container if it has a lid. Follow the healthcare worker's instruction about where to place the container. Clean your hands with soap and water. If you have been asked to collect the stool sample while at home, follow the directions provided.
There are no special instructions to follow after this test.
What are the risks?
Stool: Giving a stool sample is generally considered safe. Talk to your healthcare worker if you have questions or concerns about this test.
Ask the healthcare worker to explain the risks of this test or procedure to you before it is performed.
What are normal results for this test?
Ask your healthcare worker for the normal results of this test.
What follow up should I do after this test?
Ask your healthcare worker how you will be informed of the test results. You may be asked to call for results, schedule an appointment to discuss results, or notified of results by mail. Follow up care varies depending on many factors related to your test. Sometimes there is no follow up after you have been notified of test results. At other times follow up may be suggested or necessary. Some examples of follow up care include changes to medication or treatment plans, referral to a specialist, more or less frequent monitoring, and additional tests or procedures. Talk with your healthcare worker about any concerns or questions you have regarding follow up care or instructions.
- McRury JM & Barry RC: A modified Apt test: a new look at an old test.. Pediatr Emerg Care 1994; 10:189-191.
- Liu N, Wu AH, & Wong SS: Improved quantitative Apt test for detecting fetal hemoglobin in bloody stools of newborns. Clin Chem 1993; 39(11):2326-2329. Available from URL: http://www.clinchem.org/cgi/reprint/39/11/2326. As accessed 1/27/2005.
- Crook M: Haemoglobin in stools from neonates: measurement by a modified Apt-test. Med Lab Sci 1991; 48(4):346-347.
- Henry JB: Clinical Diagnosis and Management by Laboratory Methods, 20th ed. Saunders, 2001.