Guide to Reading Blood Test Results

Understanding blood or urine test results is essential when you go for health check-ups, as doctors often recommend blood and urine tests for patients. However, if the doctor does not explain the results, you may not understand what the figures mean. Let’s dive into how to interpret blood test results in this article.

I. What is a Blood Test?

A blood test, or hematological test, is performed on a blood sample to measure certain substances in the blood or to count various types of blood cells. Blood tests can help identify signs of disease or pathogens, check for antibodies, detect tumor markers, or evaluate the effectiveness of treatment methods.

II. Components of a Blood Test

– WBC (White Blood Cell Count):

The normal range is typically between 4,300 and 10,800 cells/mm³, equivalent to 4.3 to 10.8 x 10⁹ cells/l. An increase can indicate infections, malignancies, or leukemia, while a decrease may suggest aplastic anemia, vitamin B12 or folate deficiency, or infections.

Normal range is typically between 4,300 and 10,800 cells/mm³.

– RBC (Red Blood Cell Count):

The normal count is between 4.2 to 5.9 million cells/cm³, equivalent to 4.2 to 5.9 x 10¹² cells/l. An increase can occur due to dehydration or polycythemia, while a decrease can indicate anemia.

– HB or HBG (Hemoglobin):

Hemoglobin is a protein found in red blood cells that carries oxygen and gives red blood cells their color. Normal values vary by gender, usually ranging from 13 to 18 g/dl for men and 12 to 16 g/dl for women (equivalent to 8.1 – 11.2 millimole/l and 7.4 – 9.9 millimole/l respectively). An increase may signal dehydration, heart, or lung disease, while a decrease can indicate anemia, bleeding, or hemolytic reactions.

– HCT (Hematocrit):

This value varies by gender, typically ranging from 45 to 52% for men and 37 to 48% for women. An increase may suggest allergic disorders, polycythemia, chronic obstructive pulmonary disease, or dehydration, while a decrease may indicate bleeding, anemia, or pregnancy.

– MCV (Mean Corpuscular Volume):

This value is derived from HCT and RBC count, normally ranging from 80 to 100 femtoliters (1 femtoliters = 1/1 million liters). An increase can indicate vitamin B12 deficiency, liver disease, or hypothyroidism, while a decrease is associated with iron deficiency or thalassemia.

– MCH (Mean Corpuscular Hemoglobin):

This value is calculated by measuring hemoglobin and RBC count, with normal values ranging from 27 to 32 picograms. An increase may occur in hereditary spherocytosis, while a decrease may indicate iron deficiency anemia.

– MCHC (Mean Corpuscular Hemoglobin Concentration):

This value is derived from hemoglobin and hematocrit measurements, typically ranging from 32 to 36%. In cases of hypochromic anemia, it may be normal or low.

– PLT (Platelet Count):

• Platelets are not complete cells but fragments of cytoplasm from cells found in the bone marrow.
• They play a crucial role in blood clotting, with an average lifespan of 5 to 9 days.
• The normal range is 150,000 to 400,000/cm³ (equivalent to 150 – 400 x 10⁹/l).
• Too few platelets can cause bleeding, while too many can lead to clot formation, resulting in stroke or heart attack.
• Increases may occur in myeloproliferative disorders, while decreases can be due to chemotherapy, splenomegaly, or immune-mediated thrombocytopenia.

Lymphocytes help the body fight infections.

– LYM (Lymphocytes):

Lymphocytes play a role in fighting infections. Numerous factors can lead to decreased lymphocyte counts, including immunodeficiency, HIV/AIDS, tuberculosis, and certain cancers. The normal range is 20 to 25%.

– MXD (Mixed Cell Count):

This represents the percentage of different types of cells in the blood and can fluctuate based on the counts of each cell type.

– NEUT (Neutrophils):

The normal range is 60 to 66%. Elevated levels may indicate sepsis or bacterial infections.

Increases occur in acute bacterial infections, myocardial infarction, stress, or leukemia; decreases may occur in viral infections or aplastic anemia.

– RDW (Red Cell Distribution Width):

This value indicates the variability in red blood cell size, with a normal range of 11 to 15%. Higher values suggest greater variability and can indicate various types of anemia.

Normal RDW and:

• Increased MCV may relate to aplastic anemia.
• Normal MCV may suggest anemia in chronic diseases.
• Decreased MCV is associated with chronic disease anemia or thalassemia.

Increased RDW and:

• Increased MCV is seen in vitamin B12 or folate deficiency.
• Normal MCV indicates early iron deficiency.
• Decreased MCV can indicate iron deficiency or thalassemia.

– PDW (Platelet Distribution Width):

The normal range is 6 to 18%. Increased values may be seen in lung cancer or bacterial sepsis, while decreased values may occur in alcoholism.

– MPV (Mean Platelet Volume):

The normal range is between 6.5 to 11 fL.

Increased levels can be observed in cardiovascular diseases, diabetes, smoking, stress, and thyroid toxicity…; decreased levels may indicate aplastic anemia, megaloblastic anemia, chemotherapy for cancer, acute leukemia…

– P-LCR (Platelet Larger Cell Ratio):

The normal range is between 150 to 500 G/l (G/l = 10⁹/l).

III. What is the purpose of blood tests?

Blood tests are conducted to determine blood type and detect a wide range of diseases such as:

3.1 Blood Disorders

A general blood test can detect blood-related diseases and disorders associated with blood components, such as anemia, infections, parasitic diseases, coagulation issues, and leukemia. These conditions are diagnosed by doctors through blood test parameters such as:

Examination of red blood cells: Abnormal levels of red blood cells may indicate anemia, dehydration, hemorrhage, or other erythrocyte disorders.

Examination of white blood cells: An abnormal white blood cell count may be a sign of infection, leukemia, or immune system disorders.

Examination of platelets: Abnormal platelet levels can lead to bleeding disorders or thrombophilia.

Hemoglobin (Hb): Abnormal hemoglobin levels may indicate anemia, sickle cell anemia, thalassemia syndromes, or other blood disorders. In diabetic patients, excess blood sugar can bind with hemoglobin, resulting in increased levels of hemoglobin A1c (HbA1c).

Hematocrit (Hct): A high hematocrit indicates dehydration, while a low hematocrit may suggest anemia. Abnormal Hct levels may also be a sign of blood or bone marrow disorders.

Mean Corpuscular Volume (MCV): Abnormal MCV levels may indicate general anemia or localized anemia.
Blood tests help assess liver function.

3.2 Liver function tests (SGOT, SGPT) and kidney function

Blood tests for kidney function measure blood urea nitrogen (BUN) and creatinine levels. Both of these components are waste products filtered out of the body by the kidneys. If test results show abnormal levels, it may indicate kidney disease or dysfunction such as liver conditions like hepatitis A, B, C, E, D, cirrhosis, elevated liver enzymes, or liver cancer…

3.3 Blood Sugar Disorders

Blood tests determine the levels of glucose in your blood. Elevated blood sugar levels may indicate diabetes.

For blood tests measuring glucose, doctors will require fasting prior to blood collection to measure fasting blood sugar levels. Additionally, other blood glucose tests may be performed after meals or at any time without prior preparation.

3.4 Lipid Disorders (cholesterol, triglycerides, HDL-C)

Blood tests help doctors assess the risk of coronary heart disease in patients through cholesterol-related parameters:

Low-density lipoprotein (LDL): Leads to blockages in blood vessels, causing atherosclerosis.

High-density lipoprotein (HDL): Helps reduce arterial blockages.

Triglycerides: A type of fat found in the blood.

Abnormal cholesterol and triglyceride levels indicate a higher risk of coronary heart disease. For blood tests measuring these components, individuals will need to fast for 9 to 12 hours beforehand to ensure accuracy.

3.5 Enzyme-related Diseases

Enzymes help control and catalyze chemical reactions in the body. Blood enzyme tests are commonly used to diagnose heart attacks.

Additionally, blood tests can detect gout, HIV, evaluate the effectiveness of ongoing medications, and identify brain-related conditions such as cerebral ischemia or brain infections…

IV. Blood Testing Procedure

4.1 Before the Blood Test

For certain types of blood tests, patients may need to avoid eating for up to 12 hours.

Doctors will provide specific instructions that you must follow before undergoing tests. Depending on the type of blood test, adherence to these guidelines is crucial, as it may affect the test results, leading to potential delays or the need for retesting:

• Avoid eating or drinking (except water) for up to 12 hours.
• Stop taking certain medications.

4.2 Blood Testing Procedure

Most blood tests take only a few minutes to complete. The blood draw process can be very quick, taking 5 to 10 minutes if the vein is easily visible and accessible. Blood samples are typically taken from a vein in the arm, while samples from children are often drawn from the fingertip.

• Step 1: The doctor wraps a band around the arm to slow blood flow and make the vein more prominent, facilitating blood collection.
• Step 2: The doctor or nurse cleans the area with a disinfectant before blood sample collection.
• Step 3: A syringe needle is inserted into the vein to draw the blood sample. You may feel a slight prick when the needle goes in, but it should not be painful.
• Step 4: Once the sample is taken, the needle is removed. The doctor or nurse applies a cotton ball to the skin for a few minutes.
• Step 5: A small bandage is placed to keep the area clean.
• Step 6: After blood collection, the sample is placed in a labeled container with your name and details.

The blood sample is then sent to the laboratory for testing under a microscope or chemical analysis, depending on the required examination.

V. How to Interpret Blood Biochemistry Results

GLUCOSE is blood sugar. Normal range is from 4.1-6.1 mmol/l.

1. GLU (GLUCOSE): Blood sugar. Normal range is from 4.1-6.1 mmol/l. If it exceeds the permitted limit, blood sugar levels may either increase or decrease. Elevated levels indicate a high risk of diabetes.

2. SGOT & SGPT: Liver Enzymes

Normal range is from 9.0-48.0 for SGOT and 5.0-49.0 for SGPT. Exceeding these limits indicates impaired detoxification function of liver cells. It’s advisable to limit foods and beverages that are hard for the liver to process and affect its function, such as:
Animal fats and alcoholic beverages.

3. Lipid Profile: Including CHOLESTEROL, TRIGLYCERIDES, HDL-CHOLESTEROL, LDL-CHOLESTEROL

The normal range for these factors is as follows:

• Normal range from 3.4-5.4 mmol/l for CHOLESTEROL.
• Normal range from 0.4-2.3 mmol/l for TRIGLYCERIDES.
• Normal range from 0.9-2.1 mmol/l for HDL-Cholesterol.
• Normal range from 0.0-2.9 mmol/l for LDL-Cholesterol.

If any of the above factors exceed the acceptable limits, there is a high risk of cardiovascular diseases and hypertension. HDL-Cholesterol is considered the “good” fat; higher levels may help reduce the risk of atherosclerosis. If CHOLESTEROL levels are too high along with elevated blood pressure and LDL-Cholesterol, the risk of cardiovascular incidents and strokes is significantly increased. It’s advisable to limit the intake of fatty and high-cholesterol foods such as organ meats, poultry eggs, shrimp, crab, beef, and chicken skin… Increase physical activity. Consider garlic wine and monitor blood pressure regularly.

4. GGT (Gamma Glutamyl Transferase): An immune factor for liver cells. Normally, if liver function is good, GGT levels will be very low in the blood (from 0-53 U/L). When liver cells are overworked, their detoxification capacity decreases, leading to increased GGT levels -> Reduced immune resistance and weakened liver cell immunity, which can easily lead to liver cell failure. If a person is infected with Hepatitis B and GGT, SGOT & SGPT levels are all elevated, it is essential to use liver cell support medications and absolutely avoid alcohol, as the risk of acute hepatitis B is very high.

5. URE (Blood Urea): The most important end product of protein metabolism excreted through the kidneys.

Normal range: 2.5 – 7.5 mmol/l.

6. BUN (Blood Urea Nitrogen) = urea (mg) x 28/60; unit conversion: mmol/l x 6 = mg/dl.

• Increased in: kidney disease, high protein diet, fever, infections, urinary obstruction…
• Decreased in: low protein diet, severe liver disease, wasting…

BUN: the nitrogen in urea in the blood.

Normal range 4.6 – 23.3 mg/dl. -> BUN = mmol/l x 6 x 28/60 = mmol/l x 2.8 (mg/dl).

• Increased in: renal failure, heart failure, high protein diet, fever, infections…
• Decreased in: low protein diet, severe liver disease…

7. CRE (Creatinine): A waste product of creatine phosphate metabolism in muscles, the amount produced depends on muscle mass, filtered through the kidneys & excreted in urine; it is also the most stable protein component, unaffected by diet -> serves as a reliable measure of kidney function.

Normal range: male 62 – 120, female 53 – 100 (unit: umol/l).

• Increased in: kidney disease, heart failure, diabetes, essential hypertension, acute myocardial infarction…
• Decreased in: pregnancy, preeclampsia…

8. URIC (Uric Acid = urate): A metabolic product of purine bases (Adenine, Guanine) from DNA & RNA, primarily excreted through urine.

Normal range: male 180 – 420, female 150 – 360 (unit: umol/l).

Increased in:

• Primary: due to increased production, decreased excretion (spontaneous) -> related to enzymes: Lesch-Nyhan disease, Von Gierke disease..
• Secondary: due to increased production (tumor, psoriasis..), decreased excretion (kidney failure, medication, atherosclerosis..).
• Gout: increased uric acid in the blood may accompany tophi at joints & urate stones in the kidneys.

Decreased in: Wilson’s disease, liver cell damage..

9. IMMUNOLOGICAL RESULTS

• Anti-HBs: Antibody against hepatitis B virus in the blood (NEGATIVE)
• HbsAg: Hepatitis B virus in the blood (NEGATIVE).

10 Things Doctors Often Don’t Tell Patients About Blood Tests

1. Doctors Often Overlook Good Information

According to standard practice, doctors should discuss test results with patients. However, many maintain the belief that “no information is good,” leading them to remain silent. If a complete blood count (CBC), biochemical tests, and cholesterol levels are within normal ranges, doctors usually won’t mention it, and if they do, it’s often just sending the results without commentary.

Experts from the National Heart, Lung, and Blood Institute in the U.S. suggest that even when results are normal, professionals should inform patients to alleviate concerns and encourage better cooperation in disease prevention and treatment.

2. Normal Ranges Differ Between Males and Females

Normal test values can vary between genders, even at the same age. For example, the normal red blood cell count is typically 5-6 million cells/microliter for men but lower for women, especially postmenopausal women, where the count is only 4-5 million cells.

3. Blood Test Results Have Different Meanings Based on Age

Normal levels of hemoglobin, an indicator of anemia, also vary with age, particularly in children and adults. For children, a hemoglobin level of 11-13 grams/dl is considered normal, while for men it is 13.5-17.5 g/dl, and for adult women, it is 12-15.5 g/dl. Many other indicators also have varying normal ranges based on age.

4. A “Positive” Test Result Is Not Always Positive Information

Some tests, such as sickle cell blood tests, HIV tests, and hepatitis B tests, are deemed “positive” when disease-causing substances, DNA, or proteins are detected. In these cases, a positive test result means the individual may have the disease or has been exposed to the infectious agent in the past.

5. A “Negative” Test Result Is Often Good News

A “negative” test result is not bad or “negative.” It means that no infectious agents or risk factors for the current health status were found. For example, if blood tests are conducted for infectious diseases or rapid tests for hepatitis C, a negative result indicates good news, with no evidence of infection.

6. False Positive Results Can Happen

Sometimes, a test may return a positive result when, in fact, you do not have the disease; this is called a false positive. To ensure accuracy, multiple tests at various facilities are necessary for verification. For instance, in rapid HIV testing, false positives are quite common. In communities where 1% of the population is infected, as many as 2 out of 10 rapid HIV tests may yield false positives.

7. There Are Also False Negative Results

In reality, false negative blood test results can occur, meaning a person has a disease, but the test fails to detect it. For instance, a person with hepatitis B may test negative for HbsAg (a commonly used hepatitis B detection test) in the initial weeks to months. Thus, retesting is essential, especially for those who are continuously exposed to infectious sources.

8. Test Results Can Vary Between Medical Facilities

According to the U.S. Food and Drug Administration (FDA), referencing test results between different medical facilities is individual-specific and only for guidance. Inconsistency between laboratories is not uncommon, as test results can depend on various factors and the characteristics of each lab.

9. Abnormal Test Results May Not Always Indicate Disease

If blood test results fall outside the normal range, they may be concluded as indicative of a disease or disorder. However, some abnormalities may be temporary and not due to illness. For example, if glucose tests are conducted without fasting, or if alcohol was consumed the night before, the results at that moment could be abnormal.

10. Human Error

Although misreading blood test results is rare, it can occur. There are many causes, both subjective and objective, and sometimes doctors do not inform patients. Human error can include sample mix-ups between individuals, improper blood sampling, and issues during transportation and storage of samples before testing.

Finally, it is essential to understand that blood tests are not omnipotent; they only reflect a part of the overall picture of human health. To assess overall health status, thorough information gathering, detailed physical examinations, and many other diagnostic measures are needed. We hope the information provided will enhance your understanding of the most commonly performed tests when visiting healthcare facilities.