How to use this Manual

---

The main purpose of this Manual is to provide useful guidelines for the selection of pathology tests and to facilitate interpretation of results. The Manual consists of several sections:

Pathology requests and specimen collection

This section includes general comments on requesting laboratory tests, the collection and transport of specimens and safety issues. The correct handling of anatomical pathology specimens is also described.

Reliability of test results

This section describes some of the important variables which influence test results, the limitations of ordering tests as screening profiles and the factors which must be considered when interpreting test results and using them to guide clinical decisions.

Clinical problems

This section presents pathology tests in the context of the clinical problems which give rise to the need for diagnostic information. The tests listed are those likely to be useful, but consideration must always be given to the individual clinical situation. Where appropriate, the limitations of tests in providing definitive information are noted. Tests should never be ordered as a “routine” or “screen”; an important principle is to request tests only when the results will contribute to diagnosis and/or management.

The clinical problems section is organised in two columns; a line is inserted at the end of each entry. See illustration below.

In the first column, the main headings, or primary entries, are the “clinical problems”; subheadings in bold italic provide organisers for, as appropriate, various categories, manifestations or complications. Indented subheadings then indicate common and/or important causes, conditions, disease manifestations or complications of the problem. Entries in bold are cross-references to other primary entries, where further information can be found. Where the clinical problem has an alternative name, or is well-known by an acronym, the column one entry may simply provide a cross-reference to the alternative entry as the primary entry.

In the second column, there may be a general comment or a definition of the problem, followed by a discussion or listing of appropriate tests. Where comments or tests are appropriate only to the subsidiary entries, they appear across from those subsidiary entries. Where the subsidiary condition is described or discussed as, or under, a separate primary entry, the cross reference to that entry is provided, also in bold. In general, for ease of access, the tests are described in the same form as they appear in the test listing; exceptions to this are frequently used tests which are better known by their acronyms (eg FBC , APTT , ESR , AST , LD , FNAB ), however, these appear under their full names in the test listing. If the nature of the specimen is not stated, the required specimen is blood, plasma or serum; when the test requires other body fluids or tissue eg urine, sputum, CSF or a biopsy, the nature of the required specimen is stated. When different specimens or laboratories are involved in testing, the tests are separated by semi-colons. If a test is not described in the test listing, the comments “specialised laboratory” or “consult pathologist” (for further information) are used. If the test is described under a more general test description, a cross-reference to that test is provided in ordinary (not bold) type. If there is no entry in column two, no useful or additional pathology tests are available.



Test listing

The test listing includes most of the tests available to the clinician; occasional tests which are performed infrequently or only in highly specialised laboratories are not described. The entries are, of necessity, brief; where further information is required the reader should consult the pathologist. Test names reflect, as far as possible, common usage; alternative names for tests are included as cross-references. Other test entries, which include relevant information, are provided as cross-references. Each entry contains the following information:

TEST NAME - specimen

Specimen: Comments on the type and volume of the specimen, special requirements and precautions.
The specimen volume specified is usually the ideal, rather than the minimum. If multiple tests are being performed on one specimen, the volumes are not additive. Paediatric samples can often be smaller than those generally specified.

Method: A brief description of the methods used and/or the principles of the test.

Reference Interval: The “normal range” for results is provided where this is possible. Many are dependent on analytical method, age, gender and other variables; these variables are described.
A therapeutic interval is provided for drug assays.

Application: The indications for performing the test; situations where useful information may be gained. For some tests, comment is made on situations where testing is inappropriate or an alternative test is of more value.

Interpretation: A description of the significance of test results, factors which may influence the result, interpretation of results in specific clinical situations, comment on test sensitivity and specificity and predictive value, where possible.

Reference: One or more books or journal articles which provide further information about the test and its clinical application.

The autopsy

A discussion of the decline in autopsy rates and the importance of the autopsy to clinical practice.

Figures and Tables

Reference is made, in the text, to a number of Figures and Tables, which can be found in this section.

Glossary of abbreviations

Abbreviations have been used for convenience and have been selected on the basis of ease of understanding, common usage and convention. The abbreviations incl (for including) and esp (for especially) are used throughout the text.

Reference intervals

The reference intervals for a number of commonly used tests are provided.