Overview
Blood tests are laboratory tests where a sample of your blood is taken to diagnose any medical condition, infection, or the cause of any presenting symptom. Blood tests are an essential part of diagnosis; healthcare providers prescribe different blood tests when diagnosing your medical condition accordingly if needed. They are performed by healthcare professionals at the designated laboratories within the hospital settings or working independently. Not all blood tests require a prescription from your healthcare provider, such as checking your blood group type or general blood count, also termed CBC (Complete blood count). There are specific terms used to read the blood tests. To understand them, knowledge and understanding of those terms is a must.
What do lab results mean?
Lab results are the results that came out from the sample of blood, tissue, or urine you have given for the diagnosis in a laboratory setting. They can be positive, negative, and inclusive depending on the observations observed and concluded by healthcare professionals, i.e. microbiologists at the laboratory.
- Positive results: If a lab test result is positive, it means the medical condition or presence of bacteria, virus, or any chemical for which it was tested is present in the test. Simply put, it shows that you have the disease, bacteria, virus, or any agent for which it was tested.
- Negative results: Negative results mean the opposite of positive. For whatever reason, you were being tested is not present in the test sample you gave the laboratory. The agent that your healthcare provider was suspecting is not present in your sample given for the test, giving you a negative result.
- Inclusive results: Inclusive test results show ambiguity and confusion, and it is difficult to identify whether positive or negative. In this scenario, another test with different samples or angles will be advised in the “advisory” section of the test result to get a clear idea for an accurate diagnosis.
- A false positive: A false positive result means your test shows you have a disease or condition, but you don’t really have it.
- A false negative: A false negative result means your test shows you don’t have a disease or condition, but you really do.
Abbreviations on blood test results
Abbreviations are shortened forms of different medical terms used to save the repetition and time of writing hefty, long words. In blood test results, different abbreviations indicate parts of the test that were tested from the sample. Some of the most common abbreviations present in the blood test results are :
| ml | Milliliter |
| cmm | Cells per cubic millimeter |
| fL (femtoliter) | A fraction of one millionth of a liter |
| g/dL | Grams per deciliter |
| IU/L | International units per liter |
| mEq/L | Milliequivalent per liter |
| mg/dL | Milligrams per deciliter |
| mmol/L | Millimoles per liter |
| ng/mL | Nanograms per milliliter |
| pg (picograms) | One-trillionth of a gram |
The abbreviations in the blood tests usually follow the metric system and can help in the accurate diagnosis and dose adjustment depending on the patient.
Essential components of a blood test
Blood tests and results are composed of three essential components:
- A complete blood count
- Metabolic panel
- A lipid panel.
They are further divided into other components. Some of them are :
Complete blood count (CBC)
Complete blood count CBC focuses and consists of three tests and their measured value from the test sample for diagnostic purposes:
- White blood cells (WBCs) are responsible for autoimmunity and are usually increased in case of an infection. It also gives the absolute neutrophil count (ANC).
- Red blood cells (RBCs) carry oxygen in the body and provide details on Hemoglobin (Hgb) and hematocrit (Hct).
- Platelets are responsible for clothing in blood.
All three values are usually given in the form of a number per deciliter of blood (or with any other unit) along with the reference or normal range for that age group from which it can easily be understood and comparable to understand the difference.
The typical range of red blood cells (RBCs) falls between 4.2 and 6.1 million/mcL, with a range of 4.2-5.4 million/mcL for women and 4.7-6.1 million/mcL for men.
Blood Cells | Specimen Test Result | Reference / Normal ranges |
| RBC | 3.2mcl | 4.2-6.1mcl |
| WBC (ANC) | 3000 | 2500-6000 |
| Platelet | 12000 | 20,000 and above |
Metabolic profile
Metabolic profile checks the chemistry of the blood sample given:
- Fats (lipids)
- Proteins
- Sugar (glucose)
- Electrolytes (like potassium, magnesium, sodium, and calcium)
- Enzymes
All are represented in numbers and the reference ranges for the comparative analysis.
Lipid profile
The Lipid profile is also an essential component in the blood test, which gives the test results for cholesterol, triglyceride, LDL-cholesterol (LDL-C), and HDL-cholesterol (HDL-C) present in the body. Their ratio of presence in the body indicates underlying medical conditions accordingly. Your healthcare provider will prescribe you these tests for effective diagnostics.
The lipid profile also gives detailed information about the following:
- Proteins
- Sugar (glucose)
- Electrolytes (like potassium, magnesium, sodium, and calcium)
- Enzymes
What is the normal range for blood test results?
Normal ranges are the ranges that are considered normal and healthy in an individual. These normal or reference ranges are set after they have been tested and clinically proven on groups of people from different age groups. The average of the ranges is set as the standard for comparison. These ranges help greatly in the diagnosis and medical decision-making process.
Every component in the blood test has a normal or reference range, which is considered a standard to which the test results from a patient’s sample are compared.
When should I worry about blood test results?
If you notice drastic variations in your test results from the normal or reference ranges already mentioned in the test results, you should get yourself checked and book an appointment.
Even if they are normal and you only notice a slight difference, it’s still good to discuss it with your healthcare provider for an effective diagnosis and treatment plan for your medical condition, if there is any.
There will be a reference range given in the test result. You will compare the test result with the reference range. Usually, less than 30 nmol/L (12 ng/mL) is considered deficient and needs medical consultation and prescription to cater the deficiency.
The HCG blood test varies according to a patient’s condition. It also varies significantly in pregnant women. For non-pregnant women, less than five mIU/ml is considered normal, while for pregnant women, it lies between 1,080 and 56,500 mIU/ml, depending on the week of pregnancy (age of gestation).
