Blood Test Results and What They Mean
Many blood tests will be done before, during and after chemotherapy to monitor your child’s health.
Keeping track of results will be second nature by the end of treatment.
Blood values can be confusing. Not understanding the test and what results mean causes unnecessary stress.
Blood Values for Healthy Children
Normal reference ranges detail optimal values for different blood tests. These references vary between laboratories, and the figures in this section are only a guide.
The child’s age can impact blood values.
For example, infants and toddlers will have less granulocytes and more lymphocytes than the figures indicated below. Geographic location may also impact reference ranges.
Your Child’s Test Results
Children receiving chemotherapy experience wildly fluctuating blood counts. White cells can range from zero to higher than normal, while red cells and platelets may drop periodically, requiring transfusions.
Absolute Neutrophil Count (ANC) should be closely monitored as this gives an idea of your child’s ability to fight infections. ANC can range from zero to thousands.
Blood test results indicate how your child’s body is reacting to the chemotherapy. They do not show how effective chemotherapy is against the retinoblastoma.
Even though your child may be receiving the same protocol as another child with retinoblastoma, her body’s response to treatment will be unique.
Patterns are more important than individual results. For example, if the values of three tests are 5.0, 4.7 and 4.9, the second result is not important, but values of 5.0, 4.7 and 4.2 show a trend.
Knowing your child’s blood values is important so you can recognise patterns. If you notice an emerging pattern, or have concerns about certain levels, discuss them with the doctor.
All blood test results will be considered by your child’s medical team to gain an overall picture of her health before decisions are made about treatment.
If treatment is delayed or stopped, ask the doctor to explain the situation and revised plan. This will help you better understand what is happening to your child, which will reduce your stress.
If your child is participating in a clinical trial, consult the complete trial protocol to learn what actions should be taken by the doctors in response to specific blood test changes. If you do not have a copy of this document, ask the doctor to give you a copy to keep.
What Test Results Mean
Click on the blood test below to learn more about it, including normal ranges and potential changes during chemotherapy.
Normal Range: 11.5‑13.5 g/100ml.
Oxygen and carbon dioxide are carried through the blood by molecules within the red blood cells called haemoglobin,. Low haemoglobin is also called anaemia, symptoms of which include fatigue, pallor and shortness of breath.
As chemotherapy decreases the bone marrow’s ability to produce new red cells, low haemoglobin may occur. Your child’s haemoglobin levels will give an accurate picture of her blood’s ability to carry oxygen.
Normal Range: 34‑40%
Also called packed cell volume (PCV), Haematocrit represents the percentage of red cells in the blood. To determine the ratio of plasma (clear liquid part of blood) to red cells, a blood sample is spun in a centrifuge to separate the two products.
If your child has a Haematocrit of 25%, it means that her test produced 25% blood cells and 75% plasma. During chemotherapy, your child’s bone marrow will not manufacture many red cells, so her Haematocrit will decrease. This means she will have less oxygen in her blood, and her energy levels may become low. She may be given a transfusion of packed red cells if her Haematocrit drops below 20%.
Red Blood Cells (RBC)
Normal Range: 3.9‑5.3 m/cm or 3.9‑5.3 X 1012/L
In healthy individuals, the bone marrow continually manufactures red blood cells which transport the oxygen and carbon dioxide rich haemoglobin molecules throughout the blood stream. An automated electronic device is used to count the number of red cells per litre of blood.
The three red cell indices of MCHC, MCV and MCH are mathematical relationships of Haematocrit to haemoglobin, Haematocrit to red cell count and haemoglobin to red cell count. These are numerical expressions of the level of change identified in red cells, and the concentration of haemoglobin present within each cell. Low teens are acceptable figures, but a distorted red cell population is represented by raised indices.
Normal Range: 160,000‑500,000 mm3
Platelets help repair wounds and prevent bleeding by forming clots. In analysis, they are counted by an electronic device. As they travel through the body, approximately one third of all platelets can be found in the spleen at any given time.
Dysfunction of the spleen will therefore impact platelet counts. For example, enlargement of the spleen may cause a precipitous drop in counts, whilst its removal may result in a dramatically elevated platelet count.
A raised platelet count is known as thrombocytosis. As chemotherapy depresses bone marrow function, the production of platelets will also decrease. Low platelet count is called thrombocytopenia.
Bruising, bleeding gums and nose bleeds are symptoms of decreased platelet levels. If significant bleeding occurs, or your child’s count is very low, a transfusion may be given.
White Blood Cells (WBC)
Normal Range: 5,000‑10,000 mm3 or 5‑10 K/UL
White blood cells are the body’s natural defence against infection. As cancer treatment destroys white cells, you will need to be prepared for periods of low immunity, during which your child will be highly susceptible to serious illness.
You will need to take extra precautions during these times, to protect her from infection exposure.
An automated electronic device counts the number of white cells per litre of blood. If your lab report shows your child’s WBC as K/UL instead of MM3, multiply by 1000 to get the value in mm3. For example, if the total WBC is 0.6 K/UL, use the calculation 0.6×1000 = 600 mm3.
White Blood Cell Differential
A Complete Blood Count (CBC), will state the total white blood cell (WBC) count and a “differential”. This differential breaks down each type of white blood cell, listing them as a percentage of the total.
Normal ranges for the WBC differential are:
|White blood cell type||% of total WBCs|
|Segmented neutrophils (also called polys or segs)||50‑70%|
|Band neutrophils (also called bands)||1‑3%|
|Basophils (also called basos)||0.5‑1%|
|Eosinophils (also called eos)||1‑4%|
|Lymphocytes (also called lymphs)||12‑46%|
|Monocyles (also called monos)||2‑10%|
During recovery from low blood counts, metamyelocytes, myelocytes, promyelocytes, and myeloblasts may also be found in the blood, and may therefore be listed in lab reports. These immature white cells are usually only found in the bone marrow.
Absolute Neutrophil Count (ANC)
Absolute Neutrophil Count (also known as the Absolute Granulocyte Count or AGC) is a determination of your child’s ability to fight infection. A child with an ANC greater than 1000 is generally considered to have near normal infection fighting capacity.
If your child’s ANC drops below 1000, she becomes neutropaenic, meaning her body is not adequately able to fight infection. When the ANC is less than 500, life threatening infections can occur. Prolonged periods of neutropaenia or a dramatic drop in counts may indicate sepsis.
Calculating your child’s ANC is relatively easy. Simply add the percentages of both segmented and band neutrophils, then divide that figure by 100 and multiply by the total WBC. For example:
Segmented neutrophils = 49%
Band neutrophils = 1%
White Blood Count = 1500.
49% + 1% = 50%. 50 / 100 = 0.5 x 1500 = 750
The ANC is 750.
An ANC over 1000 is considered sufficient to fight off bacterial or fungal infection. When his ANC is this high, your child can participate in all regular social and school activities. However, closely monitoring the pattern of your child’s ANC is advisable at all times.
For example, if your child’s ANC is 1000, but you know her pattern suggests it is likely to decrease imminently, your decisions about her activities are likely to change. Your child’s hospital will give you guidelines for appropriate activities when ANC is low.
Alanine aminotransferase (ALT)
Normal Range: 0‑48 IU./I.
Also called Serum Glutamic Pyruvic Transaminase (SGPT), this test assesses liver function, and the organ‘s response to chemotherapy. If your child’s liver is not coping with the toxic effects of chemotherapy drugs, an enzyme called ALT will be released into the blood serum by damaged liver cells.
During chemotherapy, your child’s ALT levels may rise into triple figures. Some children even experience ALT elevated into the thousands. Your child’s hospital will have a protocol for decreasing or temporarily ceasing chemotherapy to let the liver recover. This may be specified in the clinical trial protocol. If you notice a change in your child’s ALT levels, discuss them and the treatment implications with her doctor.
Aspartate aminotransferase (AST)
Normal Range: 0‑36 IU./l.
Also called Serum Glutamic Oxaloacetic Transaminase.(SGOT), this is a highly concentrated enzyme found in the liver. When liver tissue is severely damaged, its cells discharge AST into the blood serum, so the level of AST present in the blood directly represents the extent of tissue damage.
During chemotherapy, your child’s AST levels may rise into the thousands if her liver is suffering toxic effects of treatment. Viral infection and reaction to anaesthetic are among the many other possible explanations for raised levels of AST.
Ask your child’s oncologist for an explanation if you notice a significant unexpected increase in AST blood levels.
Total: 0.3‑1.3 mg./dl
Direct (conjugated): 0.1‑0.4 mg./dl
Indirect (unconjugated): 0.2‑0.18 mg./dl
When red blood cells are damaged, haemoglobin is released and converted into bilirubin. The liver removes bilirubin from the blood and expels it into the bile duct, from where it is transferred to the small intestine to aid digestion.
Ordinarily, bilirubin occurs in the bloodstream only in small amounts, but your child’s levels will rise if an excessive volume of red blood cells is being destroyed, or if liver damage prevents normal excretion.
The two types of bilirubin, indirect (unconjugated) and direct (conjugated), indicate the source of raised levels.
- Increased indirect bilirubin is present when red cells are being destroyed in excess.
- Increased direct bilirubin is observed when the liver is blocked or dysfunctioning.
Jaundice (characterised by the yellow skin colour) occurs when bilirubin seeps into the tissues due to excess blood levels.
Ask your child’s doctor to explain the situation if her total bilirubin levels increase above her normal levels.
Blood urea nitrogen (BUN)
Normal Range: 10‑20 mg/dl
Urea nitrogen is an end product of protein metabolism. The BUN test is used to assess kidney function, and identify a host of disorders, including liver disease, dehydration and shock. Elevated blood urea nitrogen levels are frequently seen with kidney or liver disease.
Normal Range: 0.3‑1.1 mg/dl
Found in the blood and urine, creatinine is a by-product of protein metabolism. Levels are tested to assess kidney function and to identify the presence and extent of possible kidney disease. Creatinine Clearance Tests are used to assess kidney function, in particular their efficiency of creatinine filtration and excretion. Insufficient kidney function and renal failure frequently result in elevated creatinine levels.
Electrically conductive substances in the blood affect and regulate blood pH and hydration. They are critical for nerve and muscle function. Electrolyte analysis may look at levels of sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), chloride (Cl−) and hydrogen phosphate (HPO42−).
The results are assessed together with kidney function test results. Electrolyte imbalances can indicate dehydration or impaired kidney function.
Glomerular filtration rate (GFR)
Normal Range: 120 ML/MIN
GFR measures how fast the kidneys filter blood. A radionuclide GFR test may be done before the first cycle of chemotherapy to assess kidney function. GFR may appear falsely low in infants, breast-fed babies and children who are not well hydrated (for example because they have been fasting for a general anaesthetic).
Intravenous fluids will be infused for 3-4 hours before an isotope solution is injected into your child’s vein. A gamma camera then takes pictures to show blood supply and flow through each kidney.
Immunoglobulin G (IgG)
Normal Range: 800 – 1800
Immunoglobulins are antibodies produced by the body. IgG is a protein produced to fight bacterial and viral infections. Low levels may indicate kidney damage, while high levels indicate an established infection.
PT / PTT / INR
PTT: 25-39 seconds
PT: 11-16 seconds
INR: 0.8–1.2 seconds
Partial Thromboplastin Time (PTT), Prothrombin Tme (PT) and International Normalised Ratio (INR) measure the blood’s clotting efficiency. The results are measured in seconds. Shorter times indicate a higher risk for clots, while longer times may be a result of using heparin to flush the central line.