Neonatal jaundice: phototherapy: practice question

A Pediatrics question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pediatrics · Neonatal jaundice: phototherapy

Sample item

Which wavelength of light is most effective for phototherapy of neonatal jaundice?

ARed light, 650 to 700 nmBBlue-green light, 460 to 490 nmCInfrared lightDUltraviolet light, below 400 nm

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Blue-green light, 460 to 490 nm

Bilirubin absorbs light best at 450 to 490 nm. Phototherapy converts it to water-soluble photoisomers such as lumirubin, which are excreted without conjugation. Ultraviolet light is harmful and is not used.

Option by option

A. Red light, 650 to 700 nm
Red light is not absorbed well by bilirubin.
B. Blue-green light, 460 to 490 nm (correct)
Correct. Blue-green light at 460 to 490 nm is most effective.
C. Infrared light
Infrared gives heat and does not photoisomerise bilirubin.
D. Ultraviolet light, below 400 nm
Ultraviolet light carries a risk of skin damage.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Pediatrics question

What is the answer to this Pediatrics question?

The best answer is B, Blue-green light, 460 to 490 nm. Bilirubin absorbs light best at 450 to 490 nm.

Why is "Red light, 650 to 700 nm" not the answer?

Red light is not absorbed well by bilirubin.

Why is "Infrared light" not the answer?

Infrared gives heat and does not photoisomerise bilirubin.

Why is "Ultraviolet light, below 400 nm" not the answer?

Ultraviolet light carries a risk of skin damage.

What concept does this question test?

It tests Neonatal jaundice: phototherapy in Pediatrics. Phototherapy converts it to water-soluble photoisomers such as lumirubin, which are excreted without conjugation. Ultraviolet light is harmful and is not used.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Neonatal jaundice: phototherapy?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.