top of page

Laboratory Insights: Anemia and Blood Transfusions

During this week's blog, we will take you behind the scenes to investigate one of the more common causes of anemia -- its iron deficiency. Additionally, we will look at the pathophysiology, how the diagnosis is made, and what treatments may assist in getting the patient back to their baseline. The focus will be heavily weighted on what happens in our nation's clinical laboratories before the units of packed red cells make it to the patient bedside.

Patient history: Known blood loss (usually chronic) - pregnancy, heavy periods, gastric ulcers, diet or iron absorption issues.

Patient presentation: Pallor, tachycardia, dyspnea, generalized fatigue, dizziness, syncope, brittle nails.

The initial laboratory workup: tubes will be drawn and sent to different sections of the lab. Each tube color means something (additives or anticoagulants exists) some tubes get spun down to leave plasma/serum to be tested, while others are simply whole blood.

Blue top - clotting studies (PT, PTT, D-Dimer) - spun plasma

Yellow top - iron studies (iron, folate, transferrin) - spun serum

Mint Green top - chemistry studies (electrolytes, kidney, liver function) - spun plasma

Lavender top - hemoglobin and hematocrit as well as platelets - not spun, whole blood

Pink top - blood type (A+, O-, etc..) - spun plasma

Remember, iron is centrally located in the hemoglobin protein -- this will directly affect how oxygen is transported throughout the body. Oxygen has four sites per Hgb molecule. -- Notice the four red discs in the image above.

Classic lab results + peripheral blood smear images - assoc w/ iron deficiency anemia.

Clotting studies and general chemistry studies may be normal. Kidney function may be reduced (erythropoietin or EPO is a hormone produced by the kidneys to make more RBC's)

The patients iron, and ferritin (iron storage) levels will be markedly reduced.

Transferrin (iron binding/transport) and total iron binding capacity (TIBC) results will be elevated.

The patients H&H (HGB & HCT) will be drastically reduced as will the overall RBC size.

Normal smear

Severely anemic smear (notice the RBC's also look smaller, and pale as they lack the Hgb protein that should be packed into each RBC).

Blood type determination

This patient below is A+, meaning they have the A and D antigen (Rh factor) present on their RBC surface, they also have an anti-B present in their circulating plasma. Patients contain the antibody for the antigen they lack.

Agglutination or a positive reaction will not let the blood travel to the bottom of the gel card. A negative reaction means the blood can travel unimpeded as no Agn/Ab reaction exists.


Should/will be focused on the underlying cause

Gastric ulcer - surgery or a new medication regime

Iron issue - iron supplementation (PO or IV)

Menstruation - GYN consultation, uterine ablations, hysterectomy etc..

Dietary changes

Blood transfusions if the Hgb is < 8g/dl. Each unit of blood should raise the Hgb by 1g/dl if the bleeding has stopped.

Bottom line: Everyone's situation may be a little different.

Transfusion procedure (can vary site to site)

Physician orders blood products based on clinical history and risk/benefit analysis

Type and Antibody screen is completed in the lab - ahead of time with a pink top < 72' old

Donor red cells are checked against the patient's plasma for compatibility (crossmatch)

Acceptable Units are placed in the fridge for patient.

Nurse visits the blood bank and takes blood to the bedside

Units and patient demographics are cross checked at least twice

Vitals checked pre and post - including temperature... think febrile reaction

Nurse remains at bedside for at least 15 mins to closely watch for transfusions reactions

Blood must be transfused within 4 hours once started

We hope you enjoyed this behind-the-scenes tour of the clinical laboratory and its role in anemia. The medical technologist, lab assistants, phlebotomists, and the pathologists that work there are extremely important to the overall healthcare ecosystem. Data drives decisions and without the lab - the amount of data utilized for clinical decision making is greatly reduced.

May 29, 2023

Author: Joshua Ishmael, MBA, MLS(ASCP)CM, NRP

Pass with PASS, LLC.

16 views0 comments

Recent Posts

See All


bottom of page