Common pathology tests include complete blood count (CBC), blood glucose, lipid profile, liver function tests, kidney function tests, thyroid tests, urine routine examination and culture tests, and BMLT students should understand why each test is done, what sample it needs and how results help a doctor. This article is for education only. It does not replace medical advice, and normal ranges differ by lab, method, age and sex, so always use the reference range printed on a lab report and your lab’s procedures. Use it to organise your learning alongside your syllabus and practicals. See also our BMLT syllabus guide and lab skills guide.
How a Lab Test Moves From Sample to Report
- Pre-analytical phase: test request, patient preparation, sample collection, labelling and transport.
- Analytical phase: processing the sample, running tests, quality control and checking results.
- Post-analytical phase: verification, reporting, communication of critical values and storage of records.
Most errors happen before the sample reaches the analyser, so good collection and labelling are as important as the test itself.
Table of Common Tests
| Test | Usual sample | Purpose (in simple words) |
|---|---|---|
| Complete blood count (CBC) | Whole blood in anticoagulant (often EDTA) | Counts blood cells and hemoglobin to help detect anemia, infection and other conditions |
| ESR | Whole blood | General marker of inflammation |
| Blood glucose (fasting, post-meal, random) | Plasma or serum, often with a glycolysis inhibitor | Helps screen and monitor diabetes |
| HbA1c | Whole blood | Shows average sugar control over a few months |
| Lipid profile | Serum | Measures cholesterol and triglycerides to assess heart risk |
| Liver function tests (LFT) | Serum | Checks liver enzymes, bilirubin and proteins |
| Kidney function tests (KFT) | Serum, sometimes urine | Checks urea, creatinine and electrolytes |
| Thyroid profile | Serum | Assesses thyroid hormone levels |
| Urine routine examination | Fresh urine | Checks physical, chemical and microscopic features of urine |
| Blood culture | Blood in culture bottles | Detects bacteria or fungi in the blood |
| Widal, dengue, malaria tests | Serum or blood | Support diagnosis of specific infections |
| Blood grouping and cross-matching | Blood | Ensures safe transfusion |
Names, methods and ranges vary by lab and equipment. Always follow your lab’s SOP.
Complete Blood Count: What It Shows
A CBC reports hemoglobin, red cell count, white cell count with differential, platelet count and indices. It helps doctors assess anemia, infections, clotting problems and some blood disorders. Technologists run it on automated analysers, check flags and sometimes review a blood smear. Learn how to spot interferences like clots, lipemia or cold agglutinins that can affect results.
Biochemistry Tests: Glucose, Lipids, Liver and Kidney
- Glucose and HbA1c: screening and monitoring of diabetes. Proper fasting and timely processing are important.
- Lipid profile: total cholesterol, HDL, LDL and triglycerides. Fasting requirements depend on lab protocol.
- Liver function tests: bilirubin, enzymes such as ALT and AST, alkaline phosphatase and proteins.
- Kidney function tests: urea, creatinine, uric acid and electrolytes such as sodium and potassium.
Learn the principle behind each method, the effect of haemolysis and the importance of quality control.
Thyroid and Hormone Tests
Thyroid tests commonly include TSH, T3 and T4, and are usually done on serum using immunoassay analysers. Results guide diagnosis and monitoring of thyroid disorders. Understand storage, calibration and quality control for immunoassays, since small variations can change interpretation.
Urine Examination
A urine routine test includes physical features (colour, clarity), chemical tests (protein, glucose, ketones, pH, blood, bilirubin) and microscopy (cells, crystals, casts). Use a fresh, properly collected sample. Learn how to avoid contamination and how to report findings clearly.
Microbiology and Culture Tests
Cultures grow microbes from blood, urine, sputum or other samples to identify the cause of infection and test antibiotic sensitivity. Technologists need strict aseptic technique, correct media, incubation conditions and careful reading. Understand the importance of sample collection before antibiotics when possible and of timely processing.
Blood Bank Basics
Blood banks perform grouping, Rh typing, antibody screening and cross-matching to ensure safe transfusion. Errors can be dangerous, so double-checking identity, reagents and records is essential. Learn the protocol for storing and issuing blood components and for handling transfusion reactions in coordination with doctors.
How to Study These Tests
- Create a table for each test: sample, method, purpose, interferences, safety points.
- Link each test with 2 or 3 common conditions where it is used.
- Practise with sample reports and write simple comments.
- Learn why quality control is needed for each method.
- Revise frequently and quiz yourself or a friend.
Common Mistakes in Learning Pathology
- Memorising normal ranges without noting that they vary
- Ignoring pre-analytical errors
- Not learning the reason behind each test
- Skipping practice of sample handling
- Confusing similar tests such as ALT and AST
- Not checking units
Pre-Analytical Errors: Examples and Prevention
| Problem | Possible effect | How to prevent |
|---|---|---|
| Wrong tube or anticoagulant | Test cannot be done or results are wrong | Check the test list and tube chart before collection |
| Delay in processing | Glucose falls, cells change shape | Process or separate promptly |
| Haemolysis | Falsely high potassium and other changes | Gentle mixing, correct needle, avoid vigorous shaking |
| Mislabelling | Report for wrong patient | Label at bedside and verify identity |
| Clotted EDTA sample | Wrong counts | Mix gently right after collection |
| Contamination | False culture results | Use aseptic technique |
Practising prevention is often more valuable than fixing errors later.
Linking Tests with Common Conditions
- Anemia: CBC, peripheral smear, iron studies
- Diabetes: glucose, HbA1c, urine ketones
- Heart risk: lipid profile and related markers
- Liver problems: LFT and viral markers
- Kidney disease: urea, creatinine, urine protein
- Infections: CBC, cultures, rapid tests
- Thyroid disorders: TSH, T3, T4
When you learn a test, also learn two or three situations where doctors request it. This improves your understanding and helps in interviews.
Role of Automation and Manual Methods
Many labs use automated analysers for speed and accuracy, but manual methods still matter for small labs, teaching and backup. Learn both. Manual methods help you understand the principle, while automation teaches you quality, maintenance and workflow. In exams you may be asked to write manual procedures, and in jobs you may handle machines. Do not depend on one approach alone.
Reading a Lab Report Layout
A report usually shows patient details, sample type, test name, result, unit, reference range and flags such as high or low. It may include comments, method and date and time. Check that the patient name, age and sex match the request. Know how to write results correctly and how to avoid transcription mistakes. Clear layout and correct units reduce confusion for doctors and patients.
Point-of-Care and Rapid Tests
Rapid tests and point-of-care devices give quick results for glucose, pregnancy, malaria, dengue and other conditions. They are useful in clinics and camps, but they need correct storage, timing and interpretation. Learn to read test lines under proper light, record lot numbers and expiry dates, and confirm unusual or conflicting results with a standard method when required. Quality control also applies to rapid tests.
Biomedical Waste Management
- Segregate waste into the colour-coded bins as per local rules
- Place sharps in puncture-proof containers
- Disinfect surfaces after spills with the recommended solution
- Never mix general waste with infectious waste
- Record waste handling if your lab requires it
Proper waste handling protects staff, patients and the environment, and it is part of lab accreditation.
Mini Practice Exercises
- Write a one-line purpose for each test in the table.
- List three sample types and their containers.
- Explain why a haemolysed sample is a problem.
- Describe the steps from sample receipt to report release.
- Draw a flowchart for a blood culture.
Doing small exercises like these makes revision more active and improves memory.
Keep Learning Beyond the Syllabus
Read case-based articles from reputed medical and laboratory sources, attend seminars and ask your teachers for sample reports. Over time, you will start to see patterns, such as how anemia changes smear findings or how infections change white cell counts. This pattern recognition makes you a thoughtful technologist, not only a machine operator. Always cross-check unusual results and communicate with seniors before releasing them.
Remember that this article is educational. Real-life interpretation and treatment decisions belong to qualified doctors.
Study Group Idea
Form a small group and take turns presenting one test each week. Present the sample, method, purpose, pitfalls and a sample case. Teaching others reveals gaps in your own understanding and builds confidence for viva exams and interviews.
Final Thoughts
Understanding common pathology tests helps you in exams, internship and jobs. Focus on why each test is done, how samples are handled, how quality is ensured and how results help clinicians. Always rely on your lab’s procedures and your teachers for exact methods and ranges.
Frequently Asked Questions
What is the most common pathology test?
CBC, blood glucose and urine routine are among the most commonly requested tests.
Do I need to fast for all blood tests?
No. Fasting is needed for some tests like fasting glucose and sometimes lipid profile. Follow lab instructions.
What is the difference between serum and plasma?
Serum is the liquid after blood clots, while plasma is the liquid from anticoagulated blood.
Why is EDTA used?
EDTA prevents clotting and is commonly used for CBC samples.
Why do normal ranges differ?
They depend on methods, equipment, age, sex and population, so use the lab’s reference range.
What is a critical value?
A result so abnormal that it needs urgent communication to the doctor, as per lab policy.
What is quality control in testing?
It means running control samples to ensure tests give reliable results.
Why is labelling important?
Wrong labelling can lead to wrong reports and patient harm.
What is haemolysis?
Breakdown of red cells in a sample, which can affect some test results.
Can I interpret reports as a BMLT student?
You learn basic interpretation, but diagnosis is done by doctors. Report only as per lab policy.
What is culture and sensitivity?
A test that grows microbes and checks which antibiotics work against them.
How can I learn tests faster?
Use tables, flash cards, practise in the lab and relate each test to common conditions.
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