Screening Tests for Infants and Children
Screening (along with physical examination) is an important part of preventive health care in infants and children.
To detect iron deficiency, clinicians should determine Hct or Hb as follows:
Testing for Hb S can be done at age 6 to 9 mo 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 mo and 1 yr in children at risk of exposure (those living in housing built before 1980) and should be repeated at 24 mo. If the clinician is not sure of a child’s risk, testing should be done. Levels > 10 μg/dL (> 0.48 μmol/L) pose a risk of neurologic damage, although some experts question this threshold because they believe that any lead in the system can be toxic.
Cholesterol screening is indicated for all children between ages 9 and 11 yr and again between ages 18 and 21 yr. Most useful is a fasting lipid profile. Cholesterol screening is indicated for children between ages 1 and 8 yr and between ages 12 and 17 yr 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).
(See also Hearing Loss.)
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 yr; young children can also be tested by observing their responses to sounds made through headphones, watching their attempts to localize the sound or 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 should be done if
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:
All sexually active females aged ≤ 25 yr and those who are no longer active but have a history of an STD: Annual screening for Chlamydia trachomatis and Neisseria gonorrhoeae
Pregnant women ≤ 25 yr: Screening during their initial prenatal visit and again during the 3rd trimester
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)
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 yr; every effort should be made to preserve the confidentiality of the adolescent. Adolescents at increased risk of HIV infection (eg, 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.