Guidance

NHS numbers for newborn screening: output based specification for the blood spot card label

Updated 9 August 2021

This output based specification (OBS) is for maternity units to produce barcoded NHS number labels for newborn blood spot (NBS) screening cards. The OBS is for the production of NBS card labels with the baby’s NHS number both in human-readable numeric ‘3-3-4’ format and encoded as a GS1-128 linear barcode.

GS1 is a not-for-profit organisation that develops and maintains global standards for business communication. The best known of these standards is the barcode, a symbol printed on products that can be scanned electronically.

1. Objectives

The objective is to make sure that NBS screening laboratories receive blood spot cards (figure 1) with the baby’s NHS number represented as a GS1-128 linear barcode as well as in human-readable format on a sticky label. The sticky label also contains basic birth and demographic information (see figure 2 below for example of sticky label).

Note that the barcode on this image is produced by the card manufacturer and has nothing to do with the barcode printed on a baby’s sticky label (see figure 2).

Figure 1: newborn blood spot card

The aim is to enable all maternity units to print labels with the NHS number to give to the baby’s mother with the personal child health record (PCHR), usually before discharge from the maternity unit.

The label will include some birth and demographic information from the birth notification data set as well as the NHS number. This enables midwives and laboratories to have enough personal details about the baby to make sure that the correct labels are being attached to the NBS sample or to support management of screening in the event of IT failures.

Midwives will use these labels when they carry out NBS screening, saving time and reducing errors on both the writing and reading stages. Use of the labels also reduces data transcription error in the laboratories. Demographic details will need to be manually updated when parents move.

The use of barcoded labels will enable the NHS number to be automatically captured from a global service relation number (GSRN) when the GS1-128 linear barcode is scanned. The GSRN makes sure the patient identifier is unique across the NHS in England. This enables the NHS number to be used within the screening process and to track babies throughout the screening care pathway.

Being able to correctly identify and track the progress of babies is fundamental to reducing the risk of babies going untested or not being tested in a timely manner.

2. Label content and format

2.1 Label content

The contents of the label are derived from the personal demographics service (PDS).

Fields must be printed on the NBS label according to the format outlined in the ISB 1555 birth notifications specification. These are:

• barcoded baby’s NHS number
• baby’s NHS number (displayed under the barcode) in 3-3-4 format, for example 123 456 7890
• baby’s family name
• baby’s first given name
• baby’s birth date (CCYY-MM-DD)
• baby’s gender
• baby’s usual address line 1 (either address line 1 or address line 2 must be present)
• baby’s usual address line 2 (either address line 1 or address line 2 must be present)
• baby’s usual address line 3 (optional)
• postcode of baby’s usual address
• birth weight (g)
• ethnic category (available on the back of the NBS card – see the ethnic categories section below)
• birth order
• number of births in this confinement
• gestation age (weeks)
• mother’s family name
• mother’s first given name
• mother’s birth date (CCYY-MM-DD) (if both the mother’s birth date and NHS number are present on the birth notification, then the mother’s NHS number must be printed in preference to the mother’s date of birth)
• mother’s NHS number must be displayed in 3-3-4 format (if both the mother’s birth date and NHS number are present on the birth notification, then the mother’s NHS number must be printed in preference to the mother’s date of birth)
• GP practice name (the name of the GP practice where the mother is registered) must be present if national GP code is blank
• national GP practice code must be present if GP practice name is blank
• delivery place name
• date labels printed (CCYY-MM-DD) including the text description ‘date printed’ (see figure 2 example of a barcoded label)

2.2 Label format

The format of the label is shown in figure 2.

Figure 2: example of a barcoded NHS number label (not to scale)

Font

The font size must be a minimum of size 8.

Data fields with text description

Some data fields must have a text description preceding the field. These are:

• NHS No:
• Rank:
• Label printed on:

Data fields with units

Data fields requiring units (birth weight and gestation age) must include the units following the field. For example:

• 3175g – birth weight
• 40⁺⁰ weeks – gestation age

Mother’s NHS number or date of birth

Where a birth is notified to the personal demographics service (PDS) which contains the mother’s NHS number, then the mother’s NHS number must be printed (in 3-3-4 format) in preference to the mother’s date of birth.

Where a birth is notified to the PDS which does not contain the mother’s NHS number, then the mother’s date of birth should be printed.

Address

If ‘baby’s usual address line 1’ is insufficient to locate a baby, for example if it only depicts a house name or flat number, then ‘baby’s usual address line 2’ must be included. Where ‘address line 3’ is present this should also be printed on the label.

Delivery place name

For the purpose of identifying a baby, the ‘delivery place name’ must be the name of the hospital or maternity unit where the baby was born, not the NHS trust.

Baby’s family name and first given name

The baby’s full family name and full first given name should be printed on the label.

If space prevents the above, then the baby’s family name must be printed in full in preference to the baby’s first given name – but as much of the first given name that can be printed must also be printed.

If space then prevents this, then as much of the baby’s family name must be printed.

3. Barcode content and format

3.1 Barcode content: data requirements

Across the NHS in England, the GSRN enables the globally unique and unambiguous identification of a patient.

For further information on the GSRN data format and use for barcoded patient identification, see section 3.9.4 of the GS1 general specifications and the NHS Digital information standard DCB1077: AIDC for patient identification.

From left to right, the GSRN element string consists of:

Application identifier (AI)

An application identifier indicates the meaning of the data which follows.

For a patient, this is always 8018, as it represents a GSRN – service recipient, and the patient is the recipient of the service/care.

Data format: 4 numeric characters, fixed length

Required value: 8018

GS1 company prefix (GCP)

A GCP is a unique string of digits, issued and licensed by GS1 member organisations for the creation of GS1 identification keys, such as the GSRN. For GSRNs used across the NHS in England, this is always NHS Digital’s GCP ‘5050898’ as NHS Digital is the service provider of the NHS number.

Data format: 7 numeric characters, fixed length

Required value: 5050898

Service reference

The service reference is used by the organisation providing the service, to enable identification of each service relation.

For GSRNs used across the NHS in England, this is always the patient’s NHS number, for example 9990005451.

Data format: 10 numeric characters, fixed length

Check digit

The check digit is calculated with the Modulo 10 algorithm and makes sure the number is correctly composed and transmitted. See GS1’s online check digit calculator.

For example, the GSRN check digit for 50508989990005451 is 3. Further information can also be found in section 7.9.1 of the GS1 general specifications.

Data format: 1 numeric character, fixed length

3.2 Barcode format: GS1-128 structure and production requirements

For the OBS for barcoded NHS number labels, the GSRN must be encoded to a GS1-128 linear barcode, as shown in figure 3.

This is encoded with the GSRN data string shown in the barcode content: data requirements section, above.

Figure 3: example of GS1-128 linear barcode

The encoded data string is: (8018)505089899900054513. Please note, the brackets shown around the AI (8018) are for demonstrative purposes only and should not be encoded.

3.3 Barcode format: the double character start pattern

The GS1-128 symbology has special double character start patterns consisting of start (A, B, or C) and function 1 symbol character (FNC1). These special start characters differentiate GS1-128 barcodes from the more generalised code 128 symbols, by transmitting the symbology identifier ‘]C1’.

Start characters A, B, and C define the corresponding code set to be used initially in the symbol.

FNC1 as a start character indicates the symbol must be read and interpreted in accordance with the GS1 system.

For the OBS for barcoded NHS number labels, as the data to be encoded is purely numeric, code set C must be used to make sure the barcode is produced at the minimum length. See the barcode structure section below for further information on the GS1-128 barcode structure.

For further information on the production of GS1 compliant GS1-128 linear barcodes, system providers should refer to section 5.4 of the GS1 general specifications.

4. System requirements

4.1 System handling of the barcode

The GSRN data string which includes the GS1 application identifier, the GS1 company prefix (GCP), patient’s NHS number and GSRN check digit, is a 22-digit element string encoded to a GS1-128 linear barcode. Systems will have to both validate and process the new format by:

• recognising and discarding the application identifier ‘8018’ (positions 1 to 4)
• recognising the GS1 company prefix for NHS Digital ‘5050898’ (positions 5 to 11)
• validating the GSRN check digit (position 22) – this validation is done by the scanner; the check digit is not sent by the scanner to the host system
• returning the 10-digit NHS number (positions 12 to 21)

5. Printing requirements

5.1 Dimensions of the barcode

X-dimension should be:

• 0.170mm (0.0067”): minimum
• 0.250mm (0.0098”): target
• 0.495mm (0.0195”): maximum

Minimum symbol height for given X-dimension should be:

• 12.70mm (0.500”): for minimum X-dimension
• 12.70mm (0.500”): for target X-dimension
• 12.70mm (0.500”): for maximum X-dimension

Quiet zone: left 10X, right 10X (where X is the X-dimension)

Minimum quality specification: 1.5/05/660

Specifically, the minimum symbol height indicated is for bar height only and does not include the human readable interpretation (HRI), or in the context of this specification, the NHS number displayed in the 3-3-4 format. See the barcode terminology section below for definitions of some common barcode terms. For further information on GS1-128 symbol size specifications for GSRNs, system providers should reference table 11, in section 5.12.3.11 of the GS1 general specifications.

5.2 Label size

The following measurements are a guide as to the minimum and maximum label sizes recommended by the UK newborn screening laboratories network (UKNSLN) so the label can fit on the blood spot card.

Minimum dimensions: 6.35cm width by 3.81cm height

Maximum dimensions: 8.89cm width by 5.08cm height

The standard operation procedure specifies a minimum of 9 labels per baby to be produced.

6. Barcode verification

6.1 Verification overview

Barcode verification checks that the symbol can be scanned effectively and consistently.

It is a vital part of any barcode production process, as it assesses and grades the overall symbol quality of a barcode, in its final configuration. This provides an assurance and high level of confidence that the barcode quality is sufficient to scan in an open environment, within its intended scanning environment (for example, point of care), at all times.

6.2 Barcode quality

The process of verifying a physical sample in its final configuration provides diagnostic information about any potential symbol defects or data encoding or decoding problems, ahead of the issue occurring in the live environment.

In accordance with international standards ISO/IEC 15416, symbol quality parameters are graded between 4.0/A – 0.0F to measure the overall symbol quality. To meet compliance to GS1 standards, a minimum grade of 2.0/C is required to pass verification.

For further information on barcode verification and quality assessment, please see section 5.12.5 of the GS1 general specifications.

Some symbols which fail verification will still be readable by some barcode readers. However, it is important not to confuse scanning with verification. At best, scanning a symbol can be used to check whether a symbol can be read by that particular scanner, but it will not indicate if there are any data validation problems, or other potential issues with the printed barcode in other environments or with other hardware.

6.3 Testing process: system suppliers

Once the system supplier has developed their system to enable the functionality detailed in this specification, the system supplier must send a physical sample of the barcoded label (with personal details blacked out) to GS1 UK for barcode verification.

GS1 UK can also support by validating any soft samples (photos of barcode labels or image files of the GS1-128 barcode), to sense check the data structure and barcode type is valid, ahead of sending any physical samples for verification. Please contact healthcare@gs1uk.org for further information on how GS1 UK can support with barcode verification and validation.

6.4 Testing process: maternity unit

Once the system supplier has upgraded the installation in the maternity unit, maternity staff should send a sample to their regional newborn screening lab to verify that the sample scans. This step can also be undertaken by the system supplier on behalf of the maternity unit.

The local screening coordinator should inform the regional screening quality assurance service (SQAS) of the verification result by the laboratory.

Please note, if any label hardware or software (for example new printer, new ink, new material or new barcode generation software) is different when installed, we recommend having a revised physical sample verified.

6.5 Testing process: laboratories

Newborn screening laboratories should check the barcoded label sample to make sure the barcode scans and brings up a 22-digit GSRN. The laboratory should inform the maternity unit of the result. If the sample fails to scan and extract the NHS number correctly, the laboratory should inform the maternity unit so that they can investigate with the suppliers.

7. What to do if a barcoded NHS number label fails to scan

A barcode may fail to scan or extract the correct data for a number of reasons. The most common reason is that the wrong barcode type is used.

The GS1-128 linear barcode is intended for use exclusively with the GS1 data syntax. In other words, GS1 barcodes are used purely for the encoding of GS1 identification keys and application identifiers, as they are designed to understand and interpret GS1 data, unlike non-GS1 barcodes.

For the OBS for barcoded NHS number labels, users must make sure a GS1-128 barcode is selected when configuring the label, rather than the non-GS1 symbol type, code 128.

A code 128 barcode (or any non-GS1 barcode type) will not understand that the data encoded is a GSRN and that the NHS number needs to be extracted from the data string, hence failing to scan or read correctly.

Besides the incorrect barcode type, another common reason for a failed scan or read, is that the barcode has not been produced to the right specifications, as defined by GS1 standards. Some simple visual checks that can optimise barcode readability are listed below.

7.1 Visual checks

Do not print barcodes that are too small or too big. Ensure barcode dimensions are printed within the specified thresholds outlined in the printing requirements.

Make sure that nothing is obscuring the barcode, and that it is not damaged or creased.

Make sure there is sufficient space around the code. This is known as the quiet zone. Barcode readers use this space to understand where the barcode starts and finishes, in order to decode the data represented as lines and spaces. If there is not sufficient space on either side of the barcode, the reader is unable to detect or recognise the symbol. See the barcode structure and barcode terminology sections below.

Make sure that the barcode has been printed in the correct ‘picket fence’ orientation. This specification requires the GS1-128 barcode to be printed in the picket fence orientation (with vertical lines), not the ladder orientation (with horizontal lines).

Make sure there are no printing defects visible. Any mis-printed bars, ink spread, or visible print imperfections can cause a failed scan or incorrect data to be extracted. This can indicate that the printer hardware or label material may have a fault or is not suitable for the application.

7.2 Contact information

For further advice and support on producing GS1 compliant barcodes for the OBS for barcoded NHS number labels, please contact healthcare@gs1uk.org

8. Ethnic categories

This is a list of ethnic categories on the back of a blood spot card.

Baby’s ethnic category	Category	Description
White	A	British
White	B	Irish
White	C	Any other White background
Mixed	D	White and Black Caribbean
Mixed	E	White and Black African
Mixed	F	White and Asian
Mixed	G	Any other Mixed background
Asian	H	Indian
Asian	J	Pakistani
Asian	K	Bangladeshi
Asian	L	Any other Asian background
Black	M	Caribbean
Black	N	African
Black	P	Any other Black background
Other	R	Chinese
Other	S	Any other ethnic category
Other	Z	Not stated

9. Barcode structure

From left to right, the GS1-128 barcode structure comprises:

• left quiet zone
• the double character start pattern:
  • a start character (A, B or C)
  • the function 1 symbol character (FNC1)
• data (including the GS1 application identifier represented in character set A, B, or C)
• a symbol check character
• the stop character
• right quiet zone

10. Barcode terminology

GS1

GS1 is a not-for-profit organisation that develops and maintains global standards for business communication. The best known of these standards is the barcode, a symbol printed on products that can be scanned electronically.

Human readable interpretation (HRI)

Human readable interpretation (HRI) is the information below, beside or above a barcode or tag which is encoded in the barcode or tag and represents the same characters as carried in the barcode or tag. Within this specification, HRI is not applicable, as the NHS number in the 3-3-4 format must be displayed instead.

Ladder (orientation)

A barcode printed in ladder orientation has its lines positioned horizontally. Generally used for small cylindrical items, as the curvature of the product can affect the barcode’s readability. Within this specification, ladder orientation must not be used.

Picket fence (orientation)

A barcode printed in picket fence orientation has its lines positioned vertically. This is the most common orientation for linear barcodes. Within this specification, the GS1-128 linear barcode must be placed as picket fence orientation only.

Quiet zone

Also known as a light margin, the quiet zone is a clear space which must be present on both sides of a 1D linear symbol, or all sides of a 2D symbol. Quiet zones are crucial for most barcode types as it ensures the scanner is able to locate the barcode’s start or finder pattern, in order to understand where the data is so it can be decoded and extracted.

Symbology identifier

A symbology identifier is a sequence of characters which identifies the type of barcode symbology being scanned, for example GS1-128 = ‘]C1’ and GS1 DataMatrix = ‘]d2’. Symbology identifiers are not encoded to barcodes but are transmitted by scanners to enable systems to correctly interpret the GS1 data string encoded. For further information see section 5.1.3 of the GS1 general specifications.

X-dimension

The specified width of the narrowest element of a barcode.