Understanding Lab Report

Understanding Lab Report

When we visit a doctor, sometimes we may be asked to get some investigations done in a laboratory.

For athletes, sportspersons, pregnancy, and travel- we are asked to get lab tests to maintain health.

For people with Diabetes, Thyroid dysfunction, High Cholesterol, Kidney Disorder, Asthma, Skin rash, etc lab tests need to be done and repeated periodically to finetune treatment.

For prevention, prophylaxis, Eg, Infection control- we may be asked for lab tests

For volunteers who want to donate blood, lab tests may be done.

For getting a Fitness Certificate- as per the individual requirement, a set of tests is requested.

For a Driving License- Blood Group, Visual Acuity, Colour Vision, and Audiology are required.

For Insurance- Depending on the age, tests are requested.

For some occupations- specific lab tests may be required. Eg Food Handlers

For students traveling abroad for education - to rule out infectious diseases

We must know what sample - whether blood, sputum, urine, feces, swab, etc Whether any prior restrictions- For thyroid tests- avoid goitrogenic food Food intake- On an empty stomach for fasting blood sugar and 2 hours after food for Postprandial blood sugar.

Method of collection of sample- eg Blood is drawn from a vein with the patient in sitting posture by qualified personnel. For urine- in a sterile container got from the lab- midstream urine to be collected.

How long to wait for the result? Each investigation, depends on the processing time, quality control, and authorized signatory.

Can we interpret the microbiological lab reports always? It is better to understand why the results are within or vary from the normal range.

Any test should be meticulously done, checked, and reported.

Usually, the normal values of any parameter eg Blood Sugar is given as a range. Anything within this acceptable range is considered normal. If there is any deviation, the reason needs to be identified. Sometimes the deviations are acceptable, for Eg during Pregnancy, blood sugar is raised and sugar can be detected in urine.

Should we repeat any tests? It is better to seek a professional opinion.

Some tests are interpreted by comparing results of several tests ( eg TSH, Free T3, T4) or of the same test done at different times ( eg ESR before and after treatment)

Some test results are reported based on normative references, eg prothrombin test

Some tests require a confirmatory test before reporting as positive Eg HIV Western Blot

Some tests can be false positives Eg WIDAL, typhoid

Some tests can be false negative Eg. HIV in the window period

Some tests vary in the same individual on different days of the month Eg FSH, LH, Estrogen

Some tests are conducted for a mass population and processed together at one time for cost-effectiveness, Eg RT PCR for Covid 19

However, it is emphasized that no matter whatever the lab result suggests, only if clinical symptoms are also correlated, we can come to a conclusion and diagnosis