Preventative care for pediatrics is vital for diagnosing potential problems early on and supporting healthy growth and development. A well visit for a child should consist of a social history, physical assessment, and background on caregiver wellness and the child’s home environment.

The healthcare provider should also observe the caregiver and child’s interaction. In addition to these components, laboratory testing is also a valuable tool in pediatric preventative care. This article is a reference guide for types of pediatric labs and their appropriate timing. 

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The Significance of Regular Lab Testing in Pediatrics

Regular lab screenings in well-child visits can detect potential problems early, such as high lead levels. Proper preventative services for pediatric patients are often lacking due to time restraints, adherence, and other social barriers. Many states have low numbers of lead screening for children on Medicaid, a very important aspect of prevention. This is especially concerning because children in low-income situations are more likely to have high levels of lead in their bloodstream.

Regular lab testing for patients in every socioeconomic situation is vitally important to promote physical, mental, and developmental health. Laboratory screening in pediatrics starts early, in the newborn stage, to prevent problems before they develop. 

The Top 8 Tests for Pediatric Patients

While you might recognize many of these tests as part of an adult screening, these are also important for the pediatric population:

Comprehensive Metabolic Panel (CMP) 

The comprehensive metabolic panel (CMP) is a useful test in the care of both adults and children. It tests a variety of markers that can provide a picture of the patient’s overall health. The panel includes measurements of liver and kidney function, as well as glucose and electrolyte levels. Albumin, alkaline phosphatase, bilirubin, protein levels, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) provide information about how well the child’s liver is functioning. These are levels of proteins and enzymes in the blood that can provide information about how well the liver is detoxifying the body.

The CMP also gives the provider and caregivers information about how well the kidneys are working to filter the blood by measuring blood urea nitrogen and creatinine. Calcium, chloride, carbon dioxide, glucose, potassium, and sodium are also measured. Abnormal results can have many interpretations including kidney or liver dysfunction, dehydration, respiratory challenges, pancreatic dysfunction, and other potential diagnoses. The metabolic assessment can be used in pediatric preventative care as a screening tool and to detect metabolic conditions if the child has risk factors. 

Complete Blood Count (CBC) 

The complete blood cell count (CBC) is widely used in pediatric care for a variety of screenings, but the most common use is detecting anemia. The routine anemia screening typically occurs at 12 months, but a CBC can be ordered earlier if risk factors are present. Testing components in the CBC are red blood cells, white blood cells, platelets, hemoglobin, hematocrit, and mean corpuscular volume. Red blood cells allow for oxygen transport through the blood, low levels of these cells may indicate anemia.

‍Hemoglobin binds to oxygen and allows the red blood cells to transport oxygen to the cells. Low levels of hemoglobin are indicative of anemia. Hematocrit and mean corpuscular volume provide additional data about the oxygen-carrying capacity of the blood. Abnormal levels of these molecules can indicate anemia. White blood cells are a vital component of the immune function of the body. These cells detect and kill pathogens in the blood. High levels may indicate that an infection is present, and low levels may be concerning for impaired immune function. The platelet's main function is to allow the blood to clot, and low levels can occur when a clotting disorder is present. 

Lipid Profile 

The lipid profile of a child or adolescent can provide valuable information about metabolic and cardiovascular health. Lipid testing typically happens at about ten years old but can be drawn earlier if the provider is concerned about the child’s lipid levels. Lipid levels should be tested again between seventeen and twenty-one years of age. Components of a lipid profile include triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and total cholesterol. Triglycerides are a type of lipid in the bloodstream, and high levels can indicate a higher risk for stroke and heart disease.

Low-density lipoproteins are a type of cholesterol molecule that can build up and promote stroke, heart disease, and peripheral artery disease. HDL is often termed “good cholesterol”, and levels of this type of cholesterol can be improved through exercise and a healthy diet. HDL facilitates the transport of LDL to the liver for processing. Lipid testing in the pediatric population can provide early detection of dyslipidemia and reduce the risk of vascular disease and stroke later in life. 

Iron Studies 

Anemia screening in pediatric primary care is a cornerstone of preventative medicine. Screening for iron deficiency by testing hemoglobin and hematocrit should be done at nine to twelve months in infants born full-term. In infants born prematurely, screening for iron deficiency should be performed at age five to six months. In adolescent patients, lab testing for this condition should be performed if the patient has dietary insufficiency, heavy sports participation, changes in weight, or heavy menstrual cycles.

‍Ferritin serum analysis is an additional option for anemia screening, this method can be used around 15 to 18 months of age. Serum ferritin levels may provide better diagnostic accuracy than hemoglobin measurements. If iron deficiency is suspected, additional iron studies may be ordered. This panel often includes a peripheral blood smear, reticulocyte (immature red blood cell) count, serum iron, total iron binding capacity, and ferritin. 

Vitamin D Levels

Vitamin D is critical for bone health, moderating inflammation, supporting immune function, and developing musculoskeletal health. While technically a vitamin, this molecule functions like a hormone, affecting almost every body system. In childhood and adolescence, vitamin D plays a critical role in skeletal formation. Vitamin D is obtained through food, supplementation, and sunlight exposure. Common risk factors for deficiency are skin pigmentation, genetics, and geographic location.

Patients who live at a high latitude with limited sunlight are more at risk for vitamin D deficiency. Vitamin D supplementation for infants, especially those exclusively breastfeeding, can be beneficial early in life. Routine vitamin D screening in pediatrics is not currently recommended, but it can be performed if the practitioner suspects that the child has a deficiency. 

Thyroid Function Tests 

The thyroid is an endocrine gland that makes several hormones with varying effects on the body. These hormones have many functions but primarily dictate energy use and thermoregulation. Thyroid function testing includes measuring thyroid stimulating hormone (TSH), T4, and T3. The primary role of TSH is stimulating the thyroid to produce hormones. If the level is high, it may indicate that the thyroid is under-functioning (hypothyroidism). Conversely, if the level is low, it may be a sign that the thyroid is too active (hyperthyroidism).

T4 is the main hormone produced by the thyroid and is measured to evaluate thyroid function. T3 occurs from a T4 conversion in the liver and other tissues. Thyroid disorders in pediatrics can be severe and cause intellectual disability. Congenital hypothyroidism is present at birth and occurs when the thyroid is not producing enough hormones to meet the needs of the body.

Screening for hypothyroidism in newborns is not a widespread practice, but prompt detection and treatment can help prevent severe cognitive disabilities. If newborn screening is being performed, the ideal timeframe is 48 to 72 hours after birth. Beyond the newborn period, testing of thyroid hormones should be performed if symptoms of a thyroid disorder are present. 

Urinalysis 

A urinalysis is used to measure levels of glucose, protein, white blood cells, red blood cells, pH, ketones, nitrites, and bilirubin. If a pediatric patient has no symptoms of urinary conditions or infection, routine screening is not currently recommended. However, if the patient has urinary symptoms, such as excessive urination, pain while urinating, or cloudy urine, a urinalysis may be indicated.  

Lead Screening 

Screening for lead exposure is a vital aspect of pediatric primary care. Lead exposure poses many risks including cognitive impairment and endocrine, cardiovascular, and immune effects. Unhealthy lead levels can also affect behavior during childhood. There is no safe level of lead, even “low” levels can cause harm to children. Lead is an environmental toxin and is especially common in housing built before 1978.

Lead is common in paint that is peeling off and dust may contain lead particles. Young children are especially susceptible to lead ingestion at home because of their exploratory developmental behaviors (e.g. mouth contact with surfaces and objects). Lead may also be present in the soil surrounding homes and buildings. The clinical manifestations of lead poisoning may include reduced appetite, constipation, abdominal pain, behavior changes, and headaches. Routine lead screening should be done at one year or at six to nine months if risk factors are present (e.g. dated residential building). 

Best Practices for Pediatric Lab Testing 

Pediatric lab testing is an important part of preventative care for children of every age. There are important considerations when blood specimens are being obtained, including patient support, comfort measures, and a skilled phlebotomist. For the healthcare provider, it is important to address patient anxiety, use an evidence-based approach, and advocate for comfort measures. Implementing screening at the appropriate times and keeping up to date regarding practice updates is an additional aspect of appropriate lab testing. 

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Key Takeaways

Proactive pediatric healthcare is vital for preventing and detecting common childhood conditions. Implementing the appropriate screening tests at the right time in a child’s life can promote wellness across the lifespan. Healthcare providers should stay informed about screening test recommendations and periodicity schedules. The child’s comfort should be addressed to make the process of obtaining specimens as smooth as possible. Promoting pediatric health through appropriate screening tests is a collaborative effort between the healthcare provider, caregivers, and patient.