Global developmental delay in children: laboratory tests before specialist advice
BioMG follows French guidelines. Adapt it to the guidelines and the tests available where you practise.
Global delay (at least 2 developmental domains)
Laboratory tests
- TSH
- Free T4 (write "suspected central hypothyroidism")
- CK (boy, especially if motor delay, falls, difficulty getting up from the floor or climbing stairs, toe walking)if needednon-French guidelineDuchenne muscular dystrophy is sometimes suspected because of developmental delay or a raised CK or transaminases; raised transaminases sometimes lead to liver disease being wrongly sought and delay the diagnosis [2]. The usual warning signs are weakness, clumsiness, a Gowers sign, difficulty climbing stairs, toe-walking [2].
- Blood lead (if risk factor for lead exposure: old dilapidated housing, pica, another child poisoned)if needednon-French guidelineLead measurement is not a routine test: it is decided case by case [1]. Exposure criteria: see the page “Lead poisoning”.
- Serum ferritinif needednon-French guidelineRestrictive or vegan diet in the child or the mother, or pica: a 2017 British review then lists serum ferritin and vitamin B12, like blood lead, among the simple, inexpensive first-line tests that can identify a treatable cause (authors' proposal) [3].
- Vitamin B12if needednon-French guidelineRestrictive or vegan diet in the child or the mother, or pica: a 2017 British review then lists serum ferritin and vitamin B12, like blood lead, among the simple, inexpensive first-line tests that can identify a treatable cause (authors' proposal) [3].
Do not order
- Standard karyotype as first-line: chromosomal microarray has replaced it in the child whose delay has no known cause [1].
- Full aetiological work-up for an isolated delay in a single domain (for example a mild language delay): it does not fall within this approach [1].
- TSH alone: it does not detect central hypothyroidism; measure TSH and free T4 together [4].
Sources (7)
- Moeschler JB, Shevell M; Committee on Genetics. Comprehensive evaluation of the child with intellectual disability or global developmental delays. Pediatrics. 2014;134(3):e903-18 (rapport clinique de l'American Academy of Pediatrics).
- Birnkrant DJ, Bushby K, Bann CM, Apkon SD, Blackwell A, Brumbaugh D, et al. Diagnosis and management of Duchenne muscular dystrophy, part 1: diagnosis, and neuromuscular, rehabilitation, endocrine, and gastrointestinal and nutritional management. Lancet Neurol. 2018;17(3):251-67.
- Mithyantha R, Kneen R, McCann E, Gladstone M. Current evidence-based recommendations on investigating children with global developmental delay. Arch Dis Child. 2017;102(11):1071-1076.
- Persani L, Brabant G, Dattani M, Bonomi M, Feldt-Rasmussen U, Fliers E, et al. 2018 European Thyroid Association (ETA) guidelines on the diagnosis and management of central hypothyroidism. Eur Thyroid J. 2018;7(5):225-37.
- Assurance maladie. Nomenclature des actes de biologie médicale (NABM), version 105 : actes 1211 (TSH + T4 libre), 1520 (CPK), 0565 (plombémie), 0901 (caryotype), 1004 (hybridation sur puce à ADN en contexte postnatal), 4050 (X fragile).
- NHS England, Genomics Education Programme. GeNotes : « Presentation: Child with developmental delay or intellectual disability » (dernière révision le 04/02/2026).
- Manickam K, McClain MR, Demmer LA, et al. Exome and genome sequencing for pediatric patients with congenital anomalies or intellectual disability: an evidence-based clinical guideline of the American College of Medical Genetics and Genomics (ACMG). Genet Med. 2021;23(11):2029-2037.