Getting More Bang for Your CBC Buck: Screening for Iron Deficiency Anemia in Pregnancy

By Maggie Fischer, RN, MS
Thursday, June 14, 2018

Maggie Fischer, RN, MS


There is a high prevalence of iron deficiency anemia (IDA) in obstetric patients. Reports indicate that IDA occurs in approximately 15 to 25 percent of all pregnancies1. According to the American Pregnancy Association, anemia during pregnancy is especially concerning because it is associated with low birth weight, premature delivery and maternal mortality1. It is critical for practitioners to accurately screen and manage IDA in pregnant patients.

Practical Solution

Expanded CBC parameters available on Sysmex analyzers can provide practitioners with lab data to better screen and manage anemia. The use of the expanded parameters in high-risk populations is extremely helpful because it can alert practitioners to the presence of IDA when traditional tests are inconclusive. The reticulocyte parameters include:

  • Absolute Reticulocyte Count (#) and Percentage (%): reflects the quantity of newly produced red blood cells (RBC), indicating whether the bone marrow is producing and/or responding to therapy
  • Immature Reticulocyte Fraction (IRF): measures rate of erythropoiesis within the last 24–48 hours, indicating whether the bone marrow is producing and/or responding to therapy
  • Reticulocyte Hemoglobin Equivalent (RET-He): measure of the hemoglobin content in the reticulocytes, reflecting availability of iron in the bone marrow that can be incorporated into new RBCs.


The option for quick and inexpensive tests that do not require an added blood draw is significant. The IWK Health Centre in Nova Scotia, Canada, found the expanded CBC parameters to be extremely valuable with their maternal/fetal patient population. The following case study demonstrates how the lab data provided clinically significant information which improved the care for the expectant mother.*

Patient History/Presentation: Healthy female expecting twins presents to her physician for a routine evaluation during her third trimester of pregnancy. Patient reported feeling tired but otherwise had no complaints. The CBC results are within normal limits.

Expanded CBC Data: The reticulocyte parameters show what has occurred in the bone marrow within the last 24–48 hours, which provides a more sensitive assessment of the patient’s condition.

The high end of normal IRF and the elevated reticulocyte counts indicate hyperproliferation of the bone marrow in response to low iron stores. The extremely low RET-He shows severe iron deficiency with insufficient iron in bone marrow for reticulocyte production.

Additional Testing: Blood smear review and ferritin tests were ordered. The blood smear showed a few microcytic and hypochromic cells but overall normal with no morphological evidence of IDA. However, based on Canadian standards, the ferritin level is low (6.8; normal range 12–140) which is consistent with the low RET-He level, confirming the diagnosis of IDA.

Diagnosis: IDA secondary to pregnancy

Benefits of a Complete Reticulocyte Analysis including RET-He

  • Direct cellular measurement of erythropoietic activity in bone marrow
  • IRF at high end of normal and elevated reticulocytes (# and %) suggest hyperproliferation of the bone marrow in response to low iron stores
  • Low RET-He may indicate iron deficiency
  • Relevant data that may contribute to treatment decisions
  • Uses the same lavender tube as CBC
  • Results obtained quickly without additional drain on resources
  • Provides double the value because it can improve care for the mother and the unborn fetus

Key Takeaway

The reticulocyte parameters provide valuable laboratory data that can assist practitioners with screening and managing IDA in challenging patient populations. The quick and sensitive parameters may provide double the value with maternal/fetal medicine because it can improve care for both the mother and her unborn baby (or babies)!

Visit for more information regarding the Sysmex parameters, or contact the Sysmex Clinical Support Team at