6.6 Use of Codes for Surveillance, Data Analysis and Presentation

The following information is intended primarily for the staff of the central registry. To record ICD-10 codes, the most specific code format (i.e. Q##.#) is used. For example, frontal encephalocele is coded as Q01.0. The three-character format or group code (i.e. Q##) is commonly used only for data analysis and presentation purposes, to group and report all types of any condition. For example, when analysing and reporting all types of (total) encephalocele, the three-character format (Q01) can be used. Diagnoses coded as possible would still be excluded.

Along with the ICD-10 codes, a list with exclusions of several anomalies is provided in the ICD-10 classification system. The term “exclusion” does not necessarily mean that the case is excluded from the registry. Rather, it means that the particular anomaly is not coded using the same code or codes. For example, because “spina bifida occulta” is considered a different anomaly from the other types of spina bifida and has a specific code (Q76.0), the Q05.# ICD-10 codes are not used. Another example is cleft palate with cleft lip. If a fetus or neonate has both a cleft palate and cleft lip, the anomaly is not coded with a cleft palate code (Q35.1–Q35.9), but instead with a code listed under cleft palate with cleft lip (Q37.0–Q37.9).

It is important to keep in mind that while, for surveillance purposes, all major anomalies affecting a fetus or neonate can be coded, for data analysis and presentation, the criteria to include or exclude certain anomalies can determine which codes are used. For example, although a case might have both anencephaly (Q00.0) and lumbar spina bifida without hydrocephalus (Q05.7), for reporting purposes, the case might be analysed only with other cases of anencephaly. In addition, if an anomaly is secondary to another anomaly, such as talipes equinovarus with spina bifida, the case would be included in analyses of spina bifida (Q05.#) but not in analyses of talipes equinovarus (Q66.0 or Q66.8). However, when both anencephaly and spina bifida are present and are contiguous, this is the condition called craniorachischisis for which there is a unique ICD-10 code for that (Q00.1); therefore, anencephaly and spina bifida are not coded separately.

Examples of the assignment of codes based on clinical description are presented next.

Example 1

The following diagnosis and clinical description are provided for a neonate: “spina bifida with LS meningocele and massive hydrocephalus”

In this case, “LS” is used to abbreviate “lumbosacral”. Although the description might suggest two anomalies (spina bifida and hydrocephalus), hydrocephalus is common among children with spina bifida and it is considered a consequence of spina bifida, the primary major congenital anomaly in this case. There are specific codes for “spina bifida with hydrocephalus” in the ICD-10. The suggested ICD-10 code to assign to this case is Q05.2 (lumbosacral spina bifida with hydrocephalus). This case would not be included in analyses of hydrocephalus as a primary anomaly.

Example 2

The following diagnosis and clinical description are provided for a neonate: “cleft lip and palate”

Because it is not specified whether the soft palate, hard palate or both are affected and no information is provided regarding the laterality (sidedness) of the cleft lip, the suggested ICD-10 code is Q37.9 (unspecified cleft palate with unilateral cleft lip).

Note: for cleft palate, it is uncommon to have the detailed description available (whether the soft or hard palate is affected), unless the description is provided as a result of a surgical repair.

Example 3

The following diagnosis and clinical description are provided on a medical record: “cleft lip NOS; spina bifida NOS; ear tags”

The abbreviation “NOS” means “not otherwise specified”. The suggested ICD-10 code for cleft lip NOS is Q36.9 (cleft lip NOS) and for spina bifida NOS is Q05.9 (spina bifida, unspecified). Ear tags are considered minor anomalies; therefore, coding them is optional. If coded, the suggested ICD-10 code for ear tags is Q17.0 (preauricular appendage or tag). Although “NOS” is a valid code in the ICD-10, it is used only when there is no possibility of obtaining a better description for a specific congenital anomaly.

Example 4

The following diagnosis and clinical description are provided for a neonate: “amelia upper and lower limbs”

There are two ICD-10 codes to be assigned. One is for amelia of upper limbs: Q71.0 (congenital complete absence of the upper limb(s)); the other is for amelia of lower limbs: Q72.0 (congenital complete absence of lower limb(s)). However, for reporting and analytical purposes, it is suggested to count them only once, using the ICD-10 code Q71.0.

Example 5

The following diagnosis and clinical description are provided as part of an autopsy report: “anencephaly infant with gross abnormalities; bilateral cleft lip; cleft palate”

The suggested ICD-10 code for anencephaly is Q00.0 (anencephaly). The “gross abnormalities” description is vague, and coding is optional. If coded, the suggested ICD-10 code is Q89.9 (congenital malformation, unspecified). Although the description may suggest two anomalies (cleft lip and cleft palate), there is a specific ICD-10 code to assign to cleft palate with bilateral cleft lip. Because the type of cleft palate is not specified, the suggested ICD-10 code is Q37.8 (unspecified cleft palate with bilateral cleft lip).

Note: avoid using the Q89.9 ICD-10 code if possible, because it does not provide any specificity and it has very minimal value in congenital anomalies surveillance.

Example 6

The following diagnosis and clinical description are provided for a neonate: “myelomeningocele, T3–T4 open”

Since it is not mentioned or specified whether hydrocephalus is present or not, one can assume that the defect is “spina bifida without hydrocephalus” and code as Q05.6 (thoracic spina bifida without hydrocephalus). However, it is also possible to use the ICD-10 code Q05.9 (spina bifida, unspecified) but by using this code the specificity for lesion level would not be captured. It is recommended that the birth defect surveillance programme include information in its protocol on how to code spina bifida when hydrocephalus is not mentioned or described in medical records.

The ICD-10 (12) and references (29, 41–43) provide more information on coding and classification of congenital anomalies.