Table 1 Evaluation and follow-up of HT-1 patients identified by newborn screening

Evaluation	Initiation of therapy (baseline)	First year of life		From 1 year to 5 years of age			After 5 years of age
		Monthly	Every 3 months	Every 3 months	Every 6 months	Yearly
HT-1 markers
Blood succinylacetone^a (plasma/ blood on filter paper)	x	x^b		x			Every 6 months
Urine succinylacetone (only if blood is not available)	x	x		x			Every 6 months
Blood NTBC concentration^a		x		x			Every 6 months
Plasma amino acids (plasma/blood on filter paper)	x	x^b		x			Every 6 months^c
Laboratories for HT-1 monitoring
CBC: hemoglobin, hematocrit, WBC, platelet count	x		x			x	Yearly
Liver evaluation
Serum AFP concentration	x	x			x		Every 6 months^d
PT	x	x^e				x	Yearly
PTT	x	x^e				x	Yearly
ALT/AST	x		x^e			x	Yearly
Imaging: CT or MRI (with contrast) or ultrasound^f^,^g	x					x^c	Yearly^c
Renal studies
Renal imaging (ultrasound)^h	x
Blood chemistries: bicarbonate, BUN, creatinine	x					x	Yearly
Blood calcium and phosphate	x					x	Yearly
Urine analysis	x
Standard dietary management laboratories: if not included above, see text for more information
Developmental evaluation/ neuropsychology assessment							Before school age
Ophthalmology: slit-lamp examination	When symptomatic or at increased risk (see text for more information)

AFP, α-fetoprotein; ALT, alanine transaminase; AST, aspartate transaminase; BUN, blood urea nitrogen; CBC, complete blood count; CT, computed tomography; MRI, magnetic resonance imaging; NTBC,2-[2-nitro-4-trifluoromethylbenzoyl]-1,3-cyclohexanedione; PT, prothrombin time; PTT, partial thromboplastin time; WBC, white blood count.
Nominal group recommendation: 56% strongly agree and 44% agree.
^aPhysician has choice of blood NTBC or SA.
^bCan switch to filter paper monitoring if the same is used over time for the baseline.
^cAs needed based on compliance.
^dAny increase, immediate imaging.
^eUntil normal.
^fNeed to wait 1 week post initiation of NTBC treatment to avoid anesthetic-induced porphyric crisis.
^gUltrasound: validity is operator-dependent.
^hWhile doing liver imaging, and then only as clinically indicated after this.

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