Institute for Infectious Diseases

Preanalytics

Introduction

The term preanalytics describes the process of sample selection, collection and storage as well as sample transport to the diagnostic laboratory. In this phase, fundamental decisions are made that have a direct impact on the analytical possibilities. Many of these decisions are irreversible or, due to the possibly necessary repetition of examinations, mean an additional burden for the patient as well as higher costs (increased diagnostic effort, longer duration of clarification or hospitalization) for the health care system. The preanalytics is based on knowledge of the principles of diagnostic and clinical microbiology. Here we differentiate between the pathogen detection and the detection of an immunological response of the organism to an infection (infection serology). We take this into account by dividing our order form into two parts: the front is reserved for the detection of pathogens, while the reverse side can be used to initiate serological examinations.

Pathogen detection

Clinical microbiology has the following basic procedures:

  • microscopic pathogen detection
  • immunological pathogen detection (antigen detection)
  • molecular biological pathogen detection (nucleic acid detection)
  • cultural pathogen detection

 

The procedures mentioned place different requirements on sample material and transport, have conceptual advantages and disadvantages and are mostly used in combination to answer clinical questions. Experience has shown that the preanalytics of pathogen detection presents the greatest difficulties for clinicians.

Errors in this area often unnecessarily restrict the available analytical options and thereby limit the diagnostic significance of the test result.

Infectious Serology

In contrast to the detection of pathogens, the pre-analysis of the infection serology is less problematic. All patient samples are kept for at least 2 years (serotheque) so that additional analyzes (e.g. parallel testing of paired sera) can also be requested at a later point in time.

Info sampling

Sampling documents are currently not online

Please contact the patient administration: +41 31 632 32 65

Storage

Generally

The times given are minimum storage times.

Storage of sample material beyond the specified time frame is possible at the special request of the client.

Follow-up examinations

Additional and follow-up examinations within these time intervals are possible, provided that sufficient material is available.

Analysis results

Electronic data is available for the past 10 years.

Our collections:

Bacto-Library:

Original materials are usually kept for 3 days at room temperature. Liquors are stored in the refrigerator for 3 days. Blood cultures are incubated in the incubator until the result is positive, blood cultures that do not grow are incubated for at least 5 days.

Stools are kept in the refrigerator for 2 days. Urines for antigen detection are stored at room temperature for 2 days. Cultures that have grown are kept at room temperature for 7 days, with the exception of: Blood cultures and liquors in which all isolates are stored for 2 years at -70 ° C.

Urogenital, respiratory, stool and urine cultures, in which the grown cultures are kept for 1 day after the cultures have been completed. The isolated relevant germs are kept in the strain collection for 2 years at -70 ° C

Parasite library:

Fixed stool samples and swabs for trichomonads are kept for 1 day at room temperature. Urine samples, swabs, punctures and biopsies are stored in the refrigerator for 1 day. Positive blood smears are kept for 2 years.

Mycobacto-Library:

The original material is kept in the refrigerator for 2 days. Isolates are frozen at -70 ° C and stored in the strain collection for 2 years. The original material for the Pneumocystis carinii detection is also stored in the refrigerator for 2 days. Positive sediments are frozen at -20 ° C and stored for 2 years.

Viro-Library:

Samples are stored in the refrigerator as a whole or as prepared aliquots for 2 weeks. Aliquots of isolated viruses are stored at -80 ° C and kept in the virus library for 1 year.

Nucleo-Library:

Samples are stored in the original container in the refrigerator for 1 week, frozen aliquots of the original material are stored at -80 ° C for 1 year.

Sero-Library:

The original blood samples are stored in the refrigerator for 1 month. Aliquots of all sera / plasmas and liquors are stored at -20 ° C for 2 years. Sera from donor examinations are stored at -20 ° C for 20 years.