Screening (along with physical examination) is an important part of preventive health care in infants, children, and adolescents.
Blood tests
To detect iron deficiency, clinicians should determine hematocrit or hemoglobin as follows:
Testing for Hb S can be done at age 6 to 9 months if not done as part of neonatal screening.
Recommendations for blood testing for lead exposure vary by state. In general, testing should be done between ages 9 months and 1 year in children at risk of exposure (those living in housing built before 1980) and should be repeated at 24 months. If the clinician is not sure of a child’s risk, testing should be done. There is no safe blood lead level in children, 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 US, 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.
Cholesterol screening is indicated for all children between 9 years and 11 years of age and again between 18 years and 21 years of age. Most useful is a fasting lipid profile. Cholesterol screening is indicated for children between ages 1 year and 8 years and between ages 12 years and 17 years only if they have a family history of high cholesterol or coronary artery disease or risk factors for coronary artery disease (eg, diabetes, obesity, hypertension).
Hearing tests
(See also Hearing Impairment in Children.)
Parents may suspect a hearing deficit if their child ceases responding 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 therefore 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.
Normal Hearing in Very Young Children*
Audiometry can be done in the primary care setting; most other audiologic procedures (eg, otoacoustic emission testing, brain stem auditory evoked response) should be done by an audiologist. Conventional audiometry can be used for children beginning at about 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.
Tympanometry, another in-office procedure, can be used with children of any age and is useful for evaluating middle ear function. Abnormal tympanograms often denote eustachian tube dysfunction or the presence of middle ear fluid that cannot be detected during otoscopic examination.
Pneumatic otoscopy is helpful in evaluating middle ear status, but combining it with tympanometry is more informative than either procedure alone.
Tuberculin testing
Screening for sexually transmitted diseases
Routine laboratory screening for common sexually transmitted diseases (STDs) is indicated for sexually active adolescents (see also Chlamydial, Mycoplasmal, and Ureaplasmal Mucosal Infections : Screening).
Screening is also recommended for the following:
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All sexually active females aged < 25 years and those who are no longer active but have a history of an STD: Annual screening for Chlamydia trachomatis and Neisseria gonorrhoeae
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Pregnant women ≤ 25 years: Screening during their initial prenatal visit and again during the 3rd trimester
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Heterosexually active young men: If seen in clinical settings associated with high prevalence of STDs (eg, in adolescent and STD clinics, at entrance into correctional facilities)
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Men who have sex with men: If they have been sexually active within the previous year
Nucleic acid amplification tests (NAATs) are the most sensitive tests for detecting C. trachomatis and N. gonorrhoeae infection. NAATs using urine, cervical, and urethral specimens are available.
All adolescents should be offered HIV screening at least once by age 16 to 18 years; 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 injection drugs, or have another STD) should be tested yearly.
Adolescents should not be routinely screened for cervical dysplasia until they are age 21.
