Screening Tests for Infants, Children, and Adolescents

To detect iron deficiency, clinicians should determine hematocrit and hemoglobin at approximately 1 year of age; preterm infants often receive routine iron supplementation and are re-evaluated or screened earlier (1). Adolescents with heavy menstrual bleeding should be screened for anemia and, in some cases, underlying bleeding disorders (2).

• In term infants: At age 9 to 12 months

• In preterm infants: At age 5 to 6 months

• In menstruating adolescents: Annually if they have any of the following risk factors: moderate to heavy menses, chronic weight loss, a nutritional deficit, or participation in athletic activity

Recommendations for blood testing for lead exposure vary by state. In general, a risk assessment should be performed at all well-child visits between 6 months and 6 years of age (3). A blood lead level test should be performed if the risk assessment is positive. Universal screening at 1 and 2 years is performed in children who live in high-prevalence areas with increased risk factors such as older housing. There is no safe blood lead level in children (4), and even low blood lead levels have been shown to affect IQ, ability to pay attention, and academic achievement. Effects of lead exposure cannot be corrected. In the United States, a level > 5 mcg/dL (> 0.24 micromol/L) is now used to identify children who have been exposed to lead and who require case management (5).

Cholesterol screening is indicated for all children between 9 years and 11 years of age and again between 17 years and 21 years of age, and can be performed with a non-fasting lipid profile (6, 7). Cholesterol screening is indicated for children after 2 years of age but no later than 10 years of age if they have a family history of high cholesterol or early coronary artery disease or risk factors for coronary artery disease (eg, diabetes, obesity, hypertension).

Testing for sickle cell disease can be performed as soon as possible if screening has not been performed in the newborn period or if there is a high degree of clinical suspicion (8).

(See also Hearing Impairment in Children.)

Parents may suspect a hearing deficit if their child does not respond appropriately to noises or voices or does not understand or develop speech (see table Normal Hearing in Very Young Children).

Because hearing deficits impair language development, hearing problems must be remedied as early as possible. The clinician should seek parental input about hearing at every visit during early childhood and be prepared to do formal testing or refer to an audiologist whenever there is any question of the child’s ability to hear.

Audiometry can be performed in the primary care setting; most other audiologic procedures (eg, otoacoustic emission testing, brain stem auditory evoked response) should be performed by an audiologist.

Hearing screening begins in newborns with otoacoustic emission testing or brain stem auditory evoked response (1, 2). Conventional audiometry can be used for children beginning at approximately age 3 years; young children can also be tested by observing their responses to sounds made through headphones, watching their attempts to localize the sound, or observing them complete a simple task. Routine screening continues annually or biannually from age 4 to 10 years (3). For older children, audiometry should be performed once between 11 and 14 years, once between 15 and 17 years, and once between 18 and 21 years; testing for older children should include 6,000- and 8,000-Hz high frequencies.

Newborn Hearing Screening

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Pneumatic otoscopy is helpful in evaluating middle ear status and is recommended for the diagnosis of otitis media with effusion, which can lead to hearing loss over time (4). Tympanometry, another in-office procedure that can be used with children of any age, is useful for evaluating middle ear function, particularly if the diagnosis is uncertain after pneumatic otoscopy. Abnormal tympanograms often denote eustachian tube dysfunction or the presence of middle ear fluid that cannot be detected during otoscopic examination.

Vision screening is recommended beginning at age 3 years, or earlier if risk factors are present. In addition to the well-child visits at 3, 6, 8, 10, 12, and 15 years of age, instrument-based screening may be used to assess risk at 12 and at 24 months of age, or at any age as an alternative to an eye chart. Patients with visual acuity of < 20/40 (20/50 if < 5 years of age), or a difference of 2 lines on the eye chart between eyes, should be evaluated by an ophthalmologist (1).

Examples of Eye Charts

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This image shows examples of eye charts used for visual acuity screening in children.

YURII/stock.adobe.com

A tuberculosis screening test using a skin test (tuberculin test) or blood test (interferon-gamma release assay [IGRA]) should be performed in (1):

• Children who have been exposed to tuberculosis (eg, to an infected family member or close contact).

• Children who have a family member with a positive tuberculin test.

• Children who were born in, immigrated from, were adopted from, or had significant travel to a high-risk country (countries in Asia, the Middle East, Africa, Latin America, or the former Soviet Union).

• Children with HIV infection.

IGRA is preferred for children over 2 years old, children who are considered unlikely to return to have their skin test read, or for those who have received the Bacille Calmette-Guérin (BCG) vaccine, which can cause a false-positive skin test result (1). Tuberculin skin testing is preferred for children under 2 years of age.

Adolescents should be asked about sexual activity at health supervision visits, including the type of sexual activity and the gender of sexual partner(s) (1). When asking about sexual activity, clinicians should be clear that this is not limited to penetrative sex but may include contact that is genital, anal, oral, skin, or through sex toys. Screening recommendations for sexually transmitted infections (STIs) vary by gender and type of sexual contact (2).

Chlamydia and gonorrhea screening is recommended annually for all sexually active females; rectal or pharyngeal testing may be indicated depending upon the type of sexual contact. Young men who have sex with men should be screened for gonorrhea, chlamydia, and syphilis, including with rectal and pharyngeal testing. Other STI screening is performed in pregnant adolescents on the basis of pregnancy rather than age and is discussed elsewhere.

Nucleic acid amplification tests (NAATs) are the most sensitive tests for detecting C. trachomatis and N. gonorrhoeae infection. NAATs using urine specimens are available, obviating the need for invasive cervical or urethral specimen collection in most cases. Additional rectal and pharyngeal specimens are recommended in some populations.

All adolescents should be offered HIV screening at least once between the ages of 15 and 18 years (3); every effort should be made to preserve the confidentiality of the adolescent. Adolescents at increased risk of HIV infection (because they are sexually active, use or have used injection drugs, or have another STI) should be tested yearly.

Adolescents should not be routinely screened for cervical dysplasia until they are age 21 to 25 (see Cervical Cancer Screening and Prevention).