Before Opening the Pot

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Contents

Introduction

'Victorious warrors win first and then go to war while defeated warriors go to war first and then seek to win.'
Sun Tzu, The Art of War

Other readers might prefer references to the 'game being won in the locker room' and other sporting analogies but debate over metaphors aside, the key principle is that even before opening the pot and then before dissecting the specimen there are various steps which need to take place in order to perform cut up successfully.

Confirm Identity

The specimen should be accompanied by a request form. It is vital that the patient identifiers on the specimen pot match those on the request form and that an adequate number of identifiers are present.

There are usually three main types of patient identifiers.

At least two of these are required to consider the specimen to be properly identified.

Confirmation of identity is not a trivial matter. The consequences of transposing specimens of the same type between patients can be catastrophic and it is imperative that the person who performs the cut up is confident that whoever has sent the specimen has labelled it sufficiently.

Good practice is for the pot and request form to be checked against each other when the specimen is received by the laboratory and only passed through to cut up once satisfactory labelling has been confirmed. However, cases will occasionally slip through. Furthermore it is essential to check that the pot you are picking up belongs to the patient you believe it does.

Multiple Pots

Quite a few patients will have more than one specimen obtained during a single procedure and thus may have more than one pot per request. Some centres may adopt a policy of having a separate form for each pot in these circumstance but personal experience is that the cohort of pots are treated as a set associated with the one request form. In these cases, as well as checking that identifiers on the pots and the form match, ensure that the correct number of pots are present.

Specimen Sites

The site of each specimen should be stated on the request form. Some clinicians also write the specimen site and nature on the pot and this practice is to be encouraged.

When the site is given on the pot and the form it is again necessary to check that they correspond. Some centres may permit discretion: a designation of 'left upper back' on the form and 'left scapula' on the pot for a skin specimen may not be identical words but they denote the same anatomical region.

Nevertheless, when in doubt do not proceed but instead initiate procedures for handling a mislabelled specimen. It is better for the processing of the specimen to be delayed in order to give an accurate report than it is to cut corners and generate a report that may be wrong and harmful to the patient.

Specimen Number

If the specimen meets the requirements for adequate labelling at the time of receipt it will be allocated a specimen number. This is a unique identifier that is specific to that specimen and that specimen only. There should be no other specimen in that laboratory which ever uses that same specimen number.

A specimen number will usually have three components

For example, H456-14 would be specimen 456 in the year 2014 within the histopathology section of the laboratory. N456-14 would be specimen 456 in the year 2014 under the diagnostic cytology section of the laboratory.

The specimen number is the most precise way to refer to the specimen. Clinicians requesting cases for meetings are well advised to supply the specimen number whenever they wish to discuss a case.

If there are multiple pots for a request form these can be signified either by a letter or numerical suffix. Letters are preferable in order to reserve the numbers for the different cassettes.

For example, if a patient has skin ellipses sent from the right forearm and central abdomen under request H653-14, these would be designated as H653-14 pot A and H653-14 pot B.

When checking the pot(s) against the form do not forget the specimen number.

The specimen number may also be called the accession number.

Computer-Aided Dictation

Once the dictation of the macroscopic description begins there are various ways for that spoken description to be recorded.

The crudest method and the most inefficient is to have an assistant scribbling down the description. This approach risks terse descriptions that are inelegant, pruned to the bare essentials and possibly difficult to read by somebody who is not familiar with the process of specimen dissection. However, the approach requires little technology and in some centres may be the only feasible option for that reason.

One step up from manual transcription is to record the description into a tape-based dictaphone. This has the problem of requiring a batch of cases to be completed before the tape can be passed to a clerical colleague for transcription. In addition, if anything happens to the tape, many descriptions can be lost.

To overcome the problems with the above two methods, some laboratories employ digital dictation. In its simpler the form the macroscopic description is recorded in an electronic format that is stored on a server and is available for manual transcription immediately the case is saved. The more sophisticated version includes computer-performed voice recognition.

In either case, the pathologist will be required to log into a computer system and record the description under the correct specimen number. This means that as well as checking that the pot corresponds to the request form the pathologist must also ensure that they are logged into that same case in the computer system.

The safety net for a computer-aided dictation system is to ensure that the description for each new request begins by stating the specimen number and the patient's name. If this practice is adopted then even if the description is recorded under the wrong patient the secretary may spot the mismatch and alert the pathologist.

Recording under the wrong patient may be more likely to occur as a result of failing to log out of the previous case.

Cassette Check

The cassettes in which the specimen, or its representative samples, will be placed will be labelled with the specimen number (some laboratories also include a patient identifier). Thus, there is a requirement to ensure that the cassettes which are being used are the correct ones for that case. Errors of this sort should be a rare event but can cause a considerable amount of work to rectify if they do occur.

Clinical Details

Contrary to what sometimes appears to be a popular belief among a cohort of colleagues who send specimens, the request form should convey to the pathologist the clinical context and background to the case.

Histopathology involves the process of interpreting features and does not merely make observations in isolation. Failure to supply this context can result in suboptimal handling of the specimen and even errors in diagnosis.

As tempting as it is to enter into a polemic about inadequate clinical details at this juncture, the focus will instead be on iterating that if clinical information is present it should be considered before dissecting the specimen. Knowing why the specimen has been sent allows the pathologist to direct the examination of the specimen to answering those questions that are derived from this purpose.

Sometimes, it is necessary to apply the background medical knowledge to ascertain all of those questions. For example, if a segment of small bowel is sent with the clinical details of 'ischaemia' the surgeon is not necessarily concerned with histopathological confirmation of that diagnosis, for it will have become apparent at the time of surgery, but is instead implicitly asking if the cause of the ischaemia can be found and if the resection margins of the specimen are viable. Ascertaining the answer to the former question requires specific handling of the specimen that will only occur if the question is anticipated.

With time and practice interpretation of the clinical information becomes second nature but it is easy for pathologists who are registered medical practitioners to forget that those things that seem obvious to them may not be so to somebody who approaches specimen dissection from a background as a biomedical scientist.

Fixation

Attempting to cut up a specimen before it is properly fixed can be a mug's game. It is not unusual for a large specimen to be received 'paddling' in formalin. The generally recommended volume of formalin is at least ten times that of the specimen. Formalin that has been contaminated by blood or contents of the GI tract will benefit from changing. Large specimens often require opening or other manoeuvres to permit good access of the formalin to all aspects. Finally, it has been suggested that the penetration of tissue by formalin is at a rate of 1mm per hour.

Relevance to Exams

Professional exams which relate to the cut up of specimens may well ask questions along the lines of 'describe how you would dissect an insert name of specimen here'. The temptation is to launch straight into the actual dissection itself. However, this may well fall into a trap and throw away marks.

Questions of this sort frequently contain an implicit, hidden component and are not simply 'describe how you dissect an insert name of specimen here' but have the added element 'and indicate how you would do it safely and show us that you know about standard operating procedures'.

Hence, the answer to the question would begin along the lines of outlining the above points (which are summarised below).