A 35-year-old woman gravida 2, para 1, comes to the physician for her first prenatal visit. Pregnancy and delivery of her first child were uncomplicated. She is not sure about the date of her last menstrual period. Pelvic examination shows a uterus consistent in size with a 10-week gestation. An ultrasound examination confirms the gestational age and shows one fetus with no indication of multiple gestations. During counseling on pregnancy risks and possible screening and diagnostic tests, the patient states she would like to undergo screening for Down syndrome. She would prefer immediate and secure screening with a low risk to herself and the fetus. Which of the following is the most appropriate next step in management at this time?

Nuchal translucency, pregnancy-associated plasma protein-A, human chorionic gonadotropin

Maternal serum α-fetoprotein, human chorionic gonadotropin, unconjugated estriol, and inhibin A

A student health coordinator plans on leading a campus-wide HIV screening program that will be free for the entire undergraduate student body. The goal is to capture as many correct HIV diagnoses as possible with the fewest false positives. The coordinator consults with the hospital to see which tests are available to use for this program. Test A has a sensitivity of 0.92 and a specificity of 0.99. Test B has a sensitivity of 0.95 and a specificity of 0.96. Test C has a sensitivity of 0.98 and a specificity of 0.93. Which of the following testing schemes should the coordinator pursue?

Test C on the entire student body followed by Test A on those who are positive

Test A on the entire student body followed by Test B on those who are positive

Test A on the entire student body followed by Test C on those who are positive

Test C on the entire student body followed by Test B on those who are positive

Test B on the entire student body followed by Test A on those who are positive

A 4-year-old boy is brought to a pediatrician by his parents for a consultation after his teacher complained about his inability to focus or make friends at school. They mention that the boy does not interact well with others at home, school, or daycare. On physical examination, his vital signs are stable with normal weight, height, and head circumference for his age and sex. His general examination and neurologic examination are completely normal. A recent audiological evaluation shows normal hearing, and intellectual disability has been ruled out by a clinical psychologist. Which of the following investigations is indicated as part of his diagnostic evaluation at present?

Autism spectrum disorder screening and developmental assessment

Magnetic resonance imaging (MRI) of brain

Positron Emission Tomography (PET) scanning of head

A 3-year-old girl is brought to the physician for a well-child examination. She was born at term and has been healthy since. She can climb up and down the stairs and can pedal a tricycle. She has difficulty using a spoon to feed herself but can copy a line. She speaks in 2- to 3-word sentences that can be understood by most people. She is selfish while playing with children her age and throws tantrums quite often. She cannot put on her own shoes and socks. She does not tolerate separation from her parents. She is at 60th percentile for height and weight. Physical examination including neurologic examination reveals no abnormalities. Which of the following is the most appropriate assessment of her development?

Fine motor: Delayed | Gross motor: Normal | Language: Normal | Social skills: Delayed

Fine motor: Normal | Gross motor: Normal | Language: Delayed | Social skills: Delayed

Fine motor: Delayed | Gross motor: Delayed | Language: Normal | Social skills: Normal

Fine motor: Normal | Gross motor: Delayed | Language: Normal | Social skills: Delayed

Fine motor: Normal | Gross motor: Delayed | Language: Delayed | Social skills: Normal

A home drug screening test kit is currently being developed. The cut-off level is initially set at 4 mg/uL, which is associated with a sensitivity of 92% and a specificity of 97%. How might the sensitivity and specificity of the test change if the cut-off level is changed to 2 mg/uL?

Sensitivity = 97%, specificity = 96%

Sensitivity = 92%, specificity = 97%

Sensitivity = 95%, specificity = 98%

Sensitivity = 100%, specificity = 97%

Sensitivity = 90%, specificity = 99%

A 4-month-old boy is brought to the physician for a well-child examination. He was born at 39 weeks gestation via spontaneous vaginal delivery and is exclusively breastfed. He weighed 3,400 g (7 lb 8 oz) at birth. At the physician's office, he appears well. His pulse is 146/min, the respirations are 39/min, and the blood pressure is 78/44 mm Hg. He weighs 7.5 kg (16 lb 9 oz) and measures 65 cm (25.6 in) in length. The remainder of the physical examination is normal. Which of the following developmental milestones has this patient most likely met?

Grasps small objects between thumb and finger

Transfers objects from hand to hand

Bounces actively when held in standing position

A two-year-old female presents to the pediatrician with her mother for a routine well-child visit. Her mother is concerned that the patient is a picky eater and refuses to eat vegetables. She drinks milk with meals and has juice sparingly. She goes to sleep easily at night and usually sleeps for 11-12 hours. The patient has trouble falling asleep for naps but does nap for 1-2 hours a few times per week. She is doing well in daycare and enjoys parallel play with the other children. Her mother reports that she can walk down stairs with both feet on each step. She has a vocabulary of 10-25 words that she uses in the form of one-word commands. She is in the 42nd percentile for height and 48th percentile for weight, which is consistent with her growth curves. On physical exam, she appears well nourished. She can copy a line and throw a ball. She can follow the command to “give me the ball and then close the door.” This child is meeting her developmental milestones in all but which of the following categories?

Social and receptive language skills

This child is developmentally normal

Denver Developmental Screening Test for USMLE Step 3: High-Yield Pediatrics Lessons

DDST Basics - The First Look

A widely used screening tool to identify potential developmental problems in asymptomatic children. It is not an IQ test or a definitive diagnostic tool.
Developed by William K. Frankenburg and Josiah B. Dodds.
Applicable for children from birth up to 6 years of age.
Assesses 4 major functional domains using a total of 125 items:
- Personal-Social
- Fine Motor-Adaptive
- Language
- Gross Motor

⭐ Exam Favourite: A "Delay" is recorded if a child fails an item that 90% of children in the standardization sample successfully pass at a younger age.

The Four Domains - What We're Screening

The DDST-II assesses developmental progress across four key functional areas. It is a screening tool, not an IQ test.

Gross Motor: Movements using large muscles.
- Examples: Head control, sitting unsupported, walking, jumping.
- Assesses posture, balance, and mobility.
Fine Motor-Adaptive: Hand-eye coordination and problem-solving.
- Examples: Reaching for objects, transferring cubes, stacking blocks, drawing shapes.
- Includes tasks that require precise manual dexterity.
Language: Communication skills (both receptive and expressive).
- Examples: Responding to sounds, cooing, babbling, speaking first words (e.g., "mama," "dada"), combining words.
Personal-Social: Self-care and interaction with others.
- Examples: Social smile, recognizing familiar faces, feeding self, dressing, playing with others.

⭐ Key Distinction: The DDST is not a measure of intelligence. It identifies potential developmental delays, requiring further diagnostic evaluation. A child can have a normal IQ but still show delays in specific domains.

Making Sense of Marks - Scoring & Interpretation

Item Scoring: Each item is marked as Pass (P), Fail (F), Refusal (R), or No Opportunity (N.O.). Refusals are scored as Fails.
Item Interpretation (Age Line Method):
- Delayed: Failure on an item which >90% of children pass (age line is to the right of the entire bar).
- Caution (C): Failure on an item passed by 75-90% of children (age line falls in this zone of the bar).
Overall Test Interpretation: A flowchart guides the final call.

⭐ The DDST is a screening tool, not diagnostic. A 'Suspect' result requires re-screening in 1-2 weeks. Persistent 'Suspect' results warrant referral for definitive developmental assessment.

The DDST is a screening tool, not an IQ or diagnostic test, for children from birth to 6 years.

It assesses four domains: Personal-Social, Fine Motor-Adaptive, Language, and Gross Motor.

A “delay” is when a child fails an item that 90% of the standardisation sample has passed.

An “Abnormal” or “Suspect” result is marked by ≥2 delays in one or more sectors.

It does not predict future academic performance.

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