What Laboratory Tests Tell You

I look at my watch, 7:00am. The start of another toxic shift in a toxic ward. I receive endorsements from the outgoing nurse on duty. Today I am a ward nurse and today, the ward is swarming with patients, each with their own needs and priorities. I sigh. Another busy shift.

I think to myself, “How on earth will I be able to survive this 8-hour shift?” as I scan through my patients’ charts. I take a look at the doctors’ orders, medication sheet. IV sheet. Then I reach the colorful part of the chart where lab results are mounted. I skip it, it’s just a bunch of results anyway. They’re not that important, and besides I’ll just leave those for the doctors to analyze. I close the charts and proceed with my rounds.

Admit it, for once in our lives, we have experienced this scenario: us scanning the charts and ignoring the part where laboratory results are located. For some, looking into it may seem unnecessary, for others, they are already too busy with other nursing tasks to bother with things that we think should be the responsibility of physicians. But some of us don’t really understand is that laboratory findings give us a glimpse of what is really happening, like a window cluing us in with signs of possible health problems our patients may have.


laboratory testsOverview

We all know that laboratory tests are medical procedures wherein samples of blood, urine, or other tissues or substances in the body are being tested. We have witnessed medical technologists and phlebotomists draw out blood from our patients from time to time, we have also experienced sending stool, urine and aspirate specimen to the laboratory for testing. But do we really understand why we do this?

Laboratory tests are ordered for many reasons: it could be to find the cause of symptoms experienced by a patient, to confirm a diagnosis, and to screen for a disease (which is usually done for people of a specific age or those who have a high risk for a specific disease). Also, Laboratory tests serve to help rule out a disease or condition, assess the severity of a disease, monitor the progression of a disease and how well an organ is working or to determine whether the treatment issued is helping. Lastly, it may be ordered to verify specific events. Take for example, DNA testing after a rape, or urine testing to look for drug use. Usually, laboratory results are affected by certain diseases and conditions, and if you just take a look closely, you may be able to connect the dots, relating a condition with the findings acquired.


What do they show?

After examination, lab results are then compared to the normal values, whether they fall within the normal range or not. While there are tests that are precise and reliable indicators of specific health problems, there are also those that provide more general information that gives doctors clues to your possible health problems. After seeing your lab results, health professionals, doctors, specifically may order other tests even procedures that may help confirm a certain condition, make a diagnosis. With the use of laboratory findings, treatment may even be revised to appropriately address the condition.

However, we should be aware that there are factors that may affect the findings of laboratory tests like sex, age, race, medical history, general health, specific foods and drugs that the patient is taking. Preparation for the procedure also affects results such as how closely the nurse and patient follow preparatory instructions. Variations in laboratory techniques and variation from one laboratory to another may also influence findings.


Laboratory tests and what they tell you

As said earlier, a specific test is ordered for a specific purpose. Abnormalities in the result may indicate certain conditions. Like BUN or Blood Urea Nitrogen for example. BUN tells how well a person’s kidneys are working. An increase in creatinine normal level may mean that patient’s kidneys are not working properly. If your kidneys are not able to remove urea from the blood normally, then your BUN level may rise. While if the BUN level is low, then there is the possibility that liver disease or damage is present. It is also possible to have a low BUN level during the 2nd and 3rd trimester of pregnancy.

Prothrombin time or PT, is a blood test that measures the clotting time of the blood and can be used to check for bleeding problems and to check whether medicine to prevent blood clots is working. Prothrombin time that does not fall between normal range often suggests the presence of liver disease or injury or may be caused by treatment with blood thinners.

TSH test or thyroid stimulating hormone test is a test used to check for thyroid gland problems. High TSH levels may suggest an underactive thyroid or hypothyroidism, may indicate the presence of a pituitary gland tumor that is making too much TSH, or may even be caused by not taking enough thyroid hormone medicine for treatment of an underactive thyroid gland. While low TSH levels may be caused by an overactive thyroid gland or hyperthyroidism, secondary hypothyroidism or damage to the pituitary gland that prevents it from making TSH, taking too much thyroid medicine for treatment of an underactive thyroid gland and pregnancy during the first trimester.

As for antibody tests or what we call coombs tests, which are done to find certain antibodies that attack red blood cells, a positive result for direct coombs test means that your blood has antibodies that fight against red blood cells, caused by transfusion of incompatible blood or may be related to conditions such as hemolytic anemia, or hemolytic disease of the newborn (HDN).


Everything in the patient’s chart is there for a purpose. You don’t just order around a certain medicine because you just want to, nor do you just order to insert an IV line because it makes you feel good. No. Everything in there is designed and planned to address a specific health issue and to help the patients recover. If we just take time to really dig into laboratory findings, you may better understand why the patient is feeling the way he/she is feeling, we may better understand the patients’ condition and most of all, with a complete view of what’s really going on, we may be able to design the most appropriate treatment plan and interventions for our patients.




Daisy Jane Antipuesto RN MN

Currently a Nursing Local Board Examination Reviewer. Subjects handled are Pediatric, Obstetric and Psychiatric Nursing. Previous work experiences include: Clinical instructor/lecturer, clinical coordinator (Level II), caregiver instructor/lecturer, NC2 examination reviewer and staff/clinic nurse. Areas of specialization: Emergency room, Orthopedic Ward and Delivery Room. Also an IELTS passer.

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