Complete Blood Count (CBC): What This Common Blood Test Measures and What Your Results Mean

A complete blood count, or CBC, is a routine blood test that measures the different cells in your blood, including red blood cells, white blood cells, and platelets. It gives your healthcare provider a broad picture of your overall health and can help detect a wide range of conditions, from infections and anemia to certain blood disorders.

The Acetylcholinesterase (AChE) test measures the activity of an enzyme called acetylcholinesterase in the amniotic fluid. This fluid surrounds the baby during pregnancy and is collected through a procedure called amniocentesis. Normally, this enzyme should NOT be present in amniotic fluid because it is contained within the fetal nervous system.

This test is done to check your general health, look for signs of infection, anemia, or bleeding problems, and to help diagnose or monitor many conditions. Your provider may order it as part of a routine checkup, before surgery, or to track how a treatment or medication is affecting your blood cells over time.

This test is primarily performed when a pregnant person's maternal serum alpha-fetoprotein (AFP) screening test shows elevated levels. Elevated AFP may indicate that the baby has an open neural tube defect (such as spina bifida or anencephaly), where the baby's skin or membrane covering the spinal cord or brain is not properly closed. When there is an opening, acetylcholinesterase can leak from the baby's nervous system into the amniotic fluid.

The test is performed with a simple blood draw. A nurse or phlebotomist cleans your skin, places a band around your upper arm, and collects a small sample of blood from a vein, usually in your arm or hand. The sample is then sent to a laboratory, where an analyzer counts and measures your blood cells. The procedure usually takes only a few minutes, and you can return to your normal activities right away.

The test requires an amniocentesis procedure, where a thin needle is inserted through the abdomen into the uterus to collect a small sample of amniotic fluid. The sample is then sent to a laboratory where it is analyzed for the presence and activity of acetylcholinesterase enzyme. Results are typically available within a few days to a week.

Your results show whether the levels of your red blood cells, white blood cells, and platelets fall within the expected range. A high white blood cell count may suggest an infection or inflammation, while a low red blood cell count can point to anemia. Abnormal platelet levels may affect how well your blood clots. Keep in mind that results outside the normal range do not always mean you are sick, so your provider will review them together with your symptoms, medical history, and other tests before making a diagnosis or recommending next steps.

A POSITIVE result means acetylcholinesterase was detected in the amniotic fluid, which strongly suggests the presence of an open neural tube defect or, rarely, other conditions. A NEGATIVE result means the enzyme was not detected, making a significant neural tube defect less likely, though it does not completely rule out all birth defects.