Page Comparison

 Code mnemonic

 Rubric

 Description

openEHR equivalent 

1

NI

no information

The value is exceptional (missing, incomplete, improper). No information as to the reason for being an exceptional value is provided. This is the most general exceptional value. It is also the default exceptional value.

(same in openEHR)

2

INV

invalid

The value as represented in the instance is not an element in the constrained value domain of a variable.

Q: This seems very similar to OTH.
A: OTH is the most common specialisation of this, but is not the only case of this 

3

 OTH

other

The actual value is not an element in the constrained value domain of a variable. (e.g., concept not provided by required code system).

Q: This seems to be saying that a value has been recorded in violation of the model?
A: No, the converse: a value has not been recorded because the value is in violation of the model. Usual cases are :

• the model says it's an integer, but the correct value is not an integer, nor should it be rounded (i.e. a modeling error)
• The model supplied a list of enumerated values, and the actual value is not in the enumeration - maybe either a modeling error or a problem in terminologies such as snomed

4

  NINF

negative infinity

Negative infinity of numbers.

Modelled in Interval<T> and DV_INTERVAL<T> classes.
Note: this concept has nothing to do with null flavours or missing data.
Respectfully, I disagree: you have a special boolean flag that says that the data is missing, and assigns an interpretation of that fact. I'm not saying that the HL7 nullFlavor is the right way to model it, just pointing out that it is to do with missing data 

4

  PINF

positive infinity

Positive infinity of numbers.

Modelled in Interval<T> and DV_INTERVAL<T> classes.
Note: this concept has nothing to do with null flavours or missing data.
ditto above 

3

 UNC

unencoded

No attempt has been made to encode the information correctly but the raw source information is represented (usually in originalText).

Not currently handled explicitly in openEHR.
Q: This content can appear at any level of granularity, and usually appears at Composition level. How does HL7 handle this?
A: in this case, original text would be a reference to a portion of the text in the composition. It doesn't really add much:  the difference between no value, an UNC and an originalText and no value and an originalText is... not much. The vanishingly small use case for this is to distinguish between "I didn't try coding this in snomed" (1st case) and "I tried to code this in snomed, but couldn't" (2nd case)
Q2: if one were to use this code wouldn't one then need a place to say more, e.g. which terminology was attempted etc?
3 A2: yes, you do - actually a valueset, really, which may cross terminologies.

 DER

derived

An actual value may exist, but it must be derived from the provided information (usually an expression is provided directly).

This can happen anywhere in the data; openEHR doesn't see it as missing data / null data. The archetype shows what is derived and what is not, e.g. Apgar total from input values.
Maybe; but in some cases the value is derived from other values (which may not yet be known) using an expression, and in other cases it's given directly. I guess that in OpenEHR you would just model that directly, but it seems to me to be confusing the process of getting the value with the semantics of the values themselves.

2

UNK

unknown

A proper value is applicable, but not known.

(same in openEHR)

3

 ASKU

asked but unknown

Information was sought but not found (e.g., patient was asked but didn't know)

In openEHR, this is a legitimate response of the patient, and is not a case of missing data. See discussion above.
I really don't understand that comment; the patient responded that they didn't know, so the data is missing

4

  NAV

temporarily unavailable

Information is not available at this time but it is expected that it will be available later.

Q: What information systems can predict te future and reliably set a value like this? What use would it serve? If the data are in fact available later, they will be recorded.
Well, the answer is that there is some; like some of the other nullFlavors, the use case is small, but still valid. It's definitely questionnaire related. I don't think it matters to an information system, but a user might make use of this subtlety somehow

3

 QS

sufficient quantity

The specific quantity is not known, but is known to be non-zero and is not specified because it makes up the bulk of the material.'Add 10mg of ingredient X, 50mg of ingredient Y, and sufficient quantity of water to 100mL.' The null flavor would be used to express the quantity of water.

In openEHR, this is not missing data. It just happens to be quantitative data that is expressed in narrative form. Modelled in archetypes by allowing a narrative alternative to a quantity.
Fine, but narrative is not the same. There are systems that can figure out how to profitable use QS as a notion. Narrative is much wider.  

3

 NASK

not asked

This information has not been sought (e.g., patient was not asked)

Q: is this a missing data concept, when by definition no data is expected to be there? In any case can only apply in specific questionnaire-like situations. Should be part of design of archetypes / templates for questionnaires.
My response is the same as above; the patient wasn't asked. When does this make a difference? Probably not to a system, but maybe to a user. But why should I have to worry about this for every item in a template? generically, I may not ask, or the patient may refuse to answer, any question. Let's just build that into the infrastructure; it seems to me that these are reasonable things to have in openEHR nullFlavor, even though they may not be widely used.

3

 TRC

trace

The content is greater than zero, but too small to be quantified.

This is a laboratory concept, and has nothing to do with missing data; labs routinely specify some amounts as 'trace'.The value not in itself computable, but is usually part of an ordered set, e.g. trace, +, ++ etc.
Usually modelled in openEHR using DV_ORDINALs, e.g. for urinalysis.
Yes, no, maybe. In the lab, you may report a value, or TRC. TRC is used outside ordinals - though not as often, I agree

2

MSK

masked

There is information on this item available but it has not been provided by the sender due to security, privacy or other reasons. There may be an alternate mechanism for gaining access to this information.Note: using this null flavor does provide information that may be a breach of confidentiality, even though no detail data is provided. Its primary purpose is for those circumstances where it is necessary to inform the receiver that the information does exist without providing any detail.

(same in openEHR)

2

NA

not applicable

No proper value is applicable in this context (e.g., last menstrual period for a male).

(same in openEHR)