Table 2

Data on 15 infants referred with elevated capillary TSH in whom capillary TSH was <40 mU/L and venous fT4 was <10 pmol/L

Patient no.BW (kg)GA (weeks)Sick? (Y/N)cTSH (mU/L) (age in days)vTSH (mIU/L) (age in days)vfT4 (pmol/L)CommentFirst cTSH (mU/L) (age in days)Other cTSH (mU/L) (age in days)
True congenital hypothyroidism
 12.9539N9.5* (12)22.7 (18)4.8Probable dyshormonogenesis on radio-isotope scan23.2 (5)
 24.2242N21.8* (17)49.9 (20)8.0Confirmed CH (rising TSH on diagnostic challenge) but no imaging performed9.42 (5)
 33.5439N25.7 (6)55.0 (15)9.0Dyshormonogenesis (no mutation found)
 42.840N26.4* (18)N/A (22)7.1Dyshormonogenesis; IUGR15.3 (6)
 53.0838N14.3* (15)52.45 (24)6.6Confirmed CH but cause unknown (no uptake on RIS but on L-T4 for > 4 weeks prior to imaging)13.7 (6)
 63.5240N34.9* (14)>100 (16)6.0Dyshormonogenesis (confirmed TPO defect)10.16 (5)
 71.6628Y32.3 (4)27.0 (9)7.5Respiratory distress syndrome with small IVH in perinatal period). Confirmed CH (TSH 15.9 mU/L after >1 year on L-T4 therapy)
Status uncertain
 83.539Y15.0† (25)11.2 (29)6.6Interrupted aortic arch and Di George (died aged 3 months)10 (6)20 (16)
 91.0429Y21.0* (15)41.8 (17)7.2Down syndrome with AVSD and chronic lung disease (died aged 6 months)7.4 (6)75 (23) NB after vTFTs
 101.4931N21.0* (10)150 (15)<5.0PDA (resolved). No imaging performed. Still on L-T45.77 (5)48.4 (17) NB after vTFTs
Transient TSH elevation
 113.8340N27.0* (27)N/A (36)9.7No imaging; treatment never started16 (4)
 122.937Y15.0* (18)110 (24)4.8ECMO for Group B Streptococcus sepsis14 (14)
 133.6537N33.0* (18)75.0 (22)9.8PAX8 mutation and thyrotropin receptor polymorphism9 (6)
 143.0137Y9.8 (10)73.5 (17)5.1Renal and lung dysplasia, imperforate anus182.03 (39) NB after vTFTs
 151.0127Y11.2† (28)17.9 (36)9.4Preterm/VLBW1.49 (5) at 28 weeks GA11.8 (25)
  • *Repeat sample.†Second repeat sample.

  • AVSD, atrioventricular septal defect; BW, birthweight; CH, congenital hypothyroidism; cTSH, capillary thyroid-stimulating hormone; ECMO, extra-corporeal membrane oxygenation; fT4, free thyroxine; GA, gestational age; IUGR, intrauterine growth restriction; IVH, intraventricular haemorrhage; L-T4, levo-thyroxine; N/A, not available; NB, nota bene; PDA, patent ductus arteriosus; TPO, thyroperoxidase; TSH, thyroid-stimulating hormone; vfT4, venous free thyroxine; VLBW, very low birth weight; vTFT, venous thyroid function test.