Capurro Test What is it and what are its characteristics?

You've probably heard the Capurro test somewhere and make you curious to know what it is about, as its popularity has grown in recent times.

This test belonging to the neonatal area It is also called the Capurro Method or Capurro Scale and is used to calculate the gestational time of a newborn. If you want to know in depth what it is and what are the characteristics of the Capurro Test, keep reading so that you can delve into the subject.

What is the Capurro Test?

The Capurro Test is a tool used in neonatology to determine the gestational age of a newborn. This test focuses on the analysis of the development of five parameters of a physiological nature, which by means of different scores allows estimating the time sought.

Analysis parameters of the Capurro Test

As we mentioned earlier, the Capurro test starts from the analysis of five physiological parameters:

• Ear shape
• Mammary gland size
• Formation of the nipple
• Skin texture
• Plantar folds

Each of the parameters is assigned a score as follows:

Ear shape (Pavilion)

• Flattened, no bend (0 points)
• Upper edge partially curved (8 Points)
• Fully curved top edge (16 Points)
• Pavilion fully curved (24 points)

Mammary gland size

• Not palpable (0 Points)
• Palpable less than 5mm (5 Points)
• Palpable between 5 and 10mm (10 Points)
• Palpable greater than 10mm (15 Points)

Formation of the nipple

• Barely visible without areola (0 Points)
• Diameter less than 7.5mm, smooth and flat areola (5 Points)
• Diameter greater than 7.5mm, dotted areola, non-raised edge (10 Points)
• Diameter greater than 7.5mm, dotted areola, raised edge (15 Points)

Skin texture

• Very fine, gelatinous (0 Points)
• Fine, smooth (5 Points)
• Thicker, discreet, superficial flaking (10 Points)
• Thick, superficial cracks, peeling of hands and feet (15 Points)
• Thick, deep parchment cracks (20 Points)

Plantar folds

• No pleats (0 points)
• Badly defined marks in the previous half (5 Points)
• Well defined marks in the anterior half, grooves in the anterior half (10 Points)
• Furrows in anterior half (15 Points)
• Furrows in more than the anterior half (20 Points)

How the Capurro Scale is applied

After the parameters are clear, each of them should be measured and then the results added. To determine the final result we must make an equation in which:

(AND): represents the estimated gestational age

(P): represents the sum of the results obtained.

The equation should be done as follows:

E = 204 + P / 7

It should be noted that this, like many tests, has a subjective character, which is why it specifically speaks of an estimate of gestational age. The margin of error is plus or minus 18 days.

Gestational age ranges

After performing the Capurro test, The results can place the newborn in one of the following categories, designed from five basic parameters:

Postmature: 42 weeks or more.

I finish it: Between 37 and 41 weeks.

Mild premature: Between 35 and 36 weeks.

Moderate premature: Between 32 and 34 weeks.

Extreme premature: Less than 32 weeks.

Capurro Test Types

The use of this test is quite widespread, which is why variations have been generated to deepen in various aspects to achieve a more effective estimate. The test model that we have just shown you is known as Capurro B test, in which only physiological parameters are evaluated. Although it can be performed in all types of neonates, it is special for those who present some special condition that prevents them from being examined, such as a newborn in critical condition or with neuromuscular problems.

The Capurro A test, It is a variation that includes neurological aspects and is generally performed in babies who do not have any neuromuscular damage from trauma, infection or anesthesia. The difference with model B of the Capurro Test is that two neurological categories are added. These are: Scarf sign and head drop.

Scarf sign

In this, axillary and scapular muscle tone is measured. What should be done is to carefully take the arm of the newborn and pass it through the thorax until it reaches the neck, so that it is in the shape of a scarf. The evaluator should observe the position of the elbow and compare it with the midline. The score will be obtained as follows:

• The elbow is on the opposite axillary line (0 Points)
• The elbow is between the opposite axillary line and the midline (6 Points)
• The elbow is in full midline (12 Points)
• The elbow is in the axillary line on the same side (18 Points)

Head drop

In this parameter, the tone of the cervical muscles is measured, in order to evaluate the neurological maturity of the neonate. The score is determined as follows:

• Head dropped back fully - Angle> 270 ° (0 Points)
• Drop head with Angle between 180 ° and 270 ° (4 Points)
• Drop Head with 180 ° Angle (8 Points)
• Angle Drop Head < 180° (12 Puntos)

The sum is done in the same way and is calculated with the same equation that is designed with a general scheme that applies to both the Capurro A Test and the Capurro B Test..

Is this test reliable?

Before giving any information, it must be said that this, like many other tests, has a margin of error and that is why they are considered subjective..

The Capurro Test is used in neonates 29 weeks and older, and therefore it is especially sensitive to use in premature babies. Although the method is quite widespread in the world, it does not mean that it is infallible, since each of the parameters is quite subjective..

Some experts assure that this Test tends to overestimate the age of neonates, and supports their arguments with various early ultrasounds. However, other scientists performed the analysis based on the mother's last menstruation date and determined that there is a good correlation.

An alternative to the Capurro test is the well-known Ballard Test, which also helps us calculate the gestational age of a newborn..

We hope that after reading this article you are clear about what the Capurro test and how to apply it. However, this test should always be done by health professionals, taking into account the fragility of newborns..