The number that spikes the heart rate: You open the health fund application, see a red line, and immediately the Google search begins. Low iron, borderline cholesterol, slightly high sugar, liver functions that deviated minimally, or an inflammatory marker whose significance is unclear. Blood tests are a very important tool, but they are also a source of misunderstandings. An abnormal result is not always a disease, and a normal result does not always mean there is no problem. What determines it is the entire story.
The first mistake is to treat the laboratory range as if it were a sharp line between health and illness. Laboratory ranges are determined according to broad populations, and sometimes even a healthy person will deviate slightly from the range. A single result can be affected by a meal, incomplete fasting, physical activity, a viral illness, dehydration, medications, supplements, or even a measurement error. Therefore, a slight deviation, especially if there are no symptoms and it appears for the first time, is not always a cause for concern. On the other hand, a deviation that repeats itself, worsens, or combines with physical complaints requires attention.
Low iron is one of the results that stresses patients, and sometimes rightfully so. It is important to distinguish between iron in the blood, ferritin, and hemoglobin. Ferritin usually reflects the iron stores in the body, and hemoglobin shows whether anemia has already developed. A person can have low ferritin and still have normal hemoglobin, but feel fatigue, decreased fitness, hair loss, dizziness, or a rapid heart rate. In young women, the common reason is significant menstrual bleeding. In men and postmenopausal women, iron deficiency also necessitates thinking about blood loss from the digestive system, and therefore it is not advisable to settle for taking a supplement without understanding why the iron dropped.
Borderline cholesterol is a good example of a value that is not read alone. There is no full significance to the general cholesterol number without knowing what the level of the bad cholesterol, the good cholesterol, the triglycerides, the patient's age, smoking, blood pressure, diabetes, kidney disease, family history, and heart diseases is. A young and healthy person with a slight deviation is not similar to a 62–year–old person with diabetes, blood pressure, and smoking. In certain cases, changes in diet and physical activity are sufficient, and in other cases, medication is necessary to reduce the risk of a cardiac or cerebral event.
Fasting sugar and glycated hemoglobin are additional values that tend to provoke stress. Slightly high sugar in one test can stem from incomplete fasting, stress, illness, or medications, but if it recurs, or if the glycated hemoglobin is within the pre–diabetes or diabetes range, this is already an important opportunity for early intervention. Pre–diabetes is not a death sentence. Weight loss, physical activity, improving diet and sleep can change the trajectory. Specifically here, the deviation in red can be a gift: An early sign before cumulative damage is caused.
Elevated liver functions, especially enzymes like ALT and AST – cause many to think immediately of a severe liver disease. In practice, a slight deviation can appear due to fatty liver, alcohol, medications, strenuous physical activity, viral infections, or supplements. Nevertheless, if the deviation recurs, is high, or is accompanied by jaundice, dark urine, itching, pain in the upper right abdomen, or weight loss, investigation is needed. Fatty liver, for example, has become one of the common reasons for a rise in liver enzymes, and it is linked to abdominal obesity, diabetes, high triglycerides, and a sedentary lifestyle.
Kidney functions also require careful reading. Slightly high creatinine or a decrease in the glomerular filtration rate are not always a sign of severe kidney failure. They depend on age, muscle mass, hydration, medications, and background diseases. A muscular person can present relatively high creatinine, and a dehydrated person can show a temporary change. But a recurring decline in kidney function, protein or blood in the urine, high blood pressure, diabetes, or swelling in the legs require follow–up. The kidneys are very quiet in the early stages of disease, and therefore blood and urine tests are important even when one feels well.
A blood count is a whole world. Low hemoglobin can suggest anemia. High leukocytes can appear in infection, stress, or steroid treatment. Neutrophils and lymphocytes change according to types of infections and inflammatory states. Low or high platelets can be a temporary reaction, but also a sign that requires investigation if they are very abnormal or recur. Here it is particularly important not to interpret each number separately. Sometimes the ratios between the values, the trend over time, and the physical examination are more important than the deviation itself.
What should light up a red light? A very significant deviation, a sharp change compared to previous tests, a combination of several abnormal values, or a deviation that comes with symptoms like unexplained weight loss, prolonged fever, night sweats, bleeding, severe weakness, shortness of breath, chest pain, jaundice, dark urine, blood in the stool, or a new change in bowel habits. In such cases, one does not wait for an appointment in two months and does not settle for an internet forum.
The correct way to deal with blood tests is simple: Not to interpret alone according to a red color in the application, not to take supplements without a reason, not to stop medications because of one number, and not to ignore a recurring deviation. It is advisable to compare to previous tests, check if proper preparation for the test was made, note symptoms if there are any, and arrive at the doctor with the precise question: Is this deviation significant for me, and what is the next step.
Blood tests were not meant to scare. They were meant to help identify early problems that can be treated. Sometimes the red line is meaningless noise. Sometimes it is an important clue. The difference between them is determined not by Google, but by full medical context.
The author is a specialist in pediatrics, a sports and aviation physician, and the medical commentator for Maariv