Here is our experience (22 years) with epoxy Histotechnology for renal needle biopsies as compared with paraffin Histotechnology.

 

DIFFERENCES BETWEEN PARAFFIN HISTOTECHNOLOGY AND EPOXY (PLASTIC) HISTOTECHNOLOGY (HIGH RESOLUTION LIGHT MICROSCOPY OR HRLM) FOR RENAL BIOPSIES

Characteristic

Paraffin

Epoxy

Fixation

Single fixation (Incomplete)

Double fixation (Complete)

Embedding

Crystalline structure

Small molecular size

Loss of substance and uneven shrinkage

More than 30%

Less than 10%

Utilization resolving power LM (0.2 um)

Poor

Full utilization.

Special stains

Jones, PAS, Trichrome.

Not needed (but available)

Section thickness

More than 4um

1-2um or less

Sub cellular detail

Poor (2um)

Excellent (0.2um)

Stat turn around time

3 hs

3 hs

Regular turn around time

12 hs

12 hs.

TEM studies

Different block. Limited, blind sampling.

Same epoxy block. Total, direct sampling.

Immunohistology (same block)

Easy

Complicated (see note below)

Technical skills needed

HT / HTL

HT / HTL. EM rotation required

Costs (See costs below)

1X

2X

Special equipment needed

None

Ultra microtome.

Automatic processing

Yes

Yes

Diagnostic accuracy

Less than 52%

More than 90%

 

Note: In our Laboratories we have abandoned Glycol Methacrylate because inherent problems (3). We have no experience with Lowicryl, LR White, and LR Gold which can be also used for Immunohistology from the same block. Cell boundaries are less obvious because less shrinkage. 

Costs: I personally believe that for renal biopsies epoxy Histotechnology is cheaper than paraffin Histotechnology. When paraffin is used HRLM and TEM must be also performed. When plastics are used, paraffin embedding is saved. It also saves Pathologist time since he only examines one set of sections for HRLM-TEM studies as compared the paraffin sections with H&E and special stains and HRLM  sampling for TEM.

Photos available in the Internet: Search for Glomerulopathies > images, in Goggle and/or Yahoo.

 
REFERENCES

1. Hoffmann EO: High Resolution Light Microscopy for the interpretation of renal biopsies. Pedriatr Nephrol (1995) 9:763-769.

2. Hoffmann EO, Rodriguez FH, Borroso E: Sub cellular light microscopy in the diagnosis of renal diseases. Patologia (1995) 28:29-38.

3. Flores TR, Hoffmann EO: Improved High Resolution Light Microscopy and Transmission Electron Microscopy Techniques in Diagnostic Pathology. J. Histotech (1997) 20:45-52.

4. Flores TR, Hoffmann EO, Velasquez M: Stat High Resolution Light Microscopy (HRLM)-Transmission Electron Microscopy (TEM) techniques for Transplant Renal Biopsies. J. Histotech (1998) 21:213-217.

 

 Ernesto Hoffmann  and Teresa Flores.

_________________________________________________________________________________________________________ 

SAME THING, DIFFERENT LAYOUT

 

Subject: Paraffin vs. plastic for renal biopsies.

Dear Kim: Here is our experience (22 years) with epoxy Histotechnology for renal needle biopsies as compared with paraffin Histotechnology.

 

DIFFERENCES BETWEEN PARAFFIN HISTOTECHNOLOGY AND EPOXY (PLASTIC) HISTOTECHNOLOGY (HIGH RESOLUTION LIGHT MICROSCOPY OR HRLM) FOR RENAL BIOPSIES

Paraffin = P; Epoxy = E

1. FIXATION. P: Single fixation (Incomplete) / E: Double fixation (Complete).

2. EMBEDDING. P: Crystalline structure, poor infiltration. / E: Small molecular size, good infiltration.

3. BEST FIXATION. P: Not practical, P will not infiltrate. E: Possible,  E will easily infiltrate.

4. SECTION THICKNESS. P: More than 4um. / E: 1-2um or less.

5. LOSS OF SUBSTANCE AND UNEVEN SHRINCAGE. P: More than 30% / E: Less than 10%.

6. SPECIAL STINS NEEDED. P: Jones, PAS, Trichrome. / E: Not needed (available but complicated).

7. TURN AROUN TIME. P: Regular 12 hr. Stat 3 hr. / E: Regular 12 hr. Stat 3 hr.                    

8. IMMUNOHISTOLOGY (SAME BLOCK). P: Easy. / E: Complicated (see note below).

9. TEM STUDIES: P: Separate block, limited blind sampling. / E-Same block, complete direct sampling.

10. AUTOMATIC PROCESSING.     P: Yes. / E: Yes.    

11. TECHNICAL SKILLS:  P: HT / HTL. / E: HT / HTL. EM rotation required.

12. SPECIAL EQUIPMENT FOR HISTO LAB. P: None. / E: Ultra microtome.

13. UTILIZATION RESOLVING POWER LM. P: Poor (2um). /  E: Excellent (0.2 um).                            

14. DIAGNOSTIC ACCURACY. P: Less than 52%. / E: More than 90%.

15. COSTS (SEE COSTS BELOW). P: 1X. / E: 2X.

 

Note: In our Laboratories we have abandoned Glycol Methacrylate because inherent problems (3). We have no experience with Lowicryl, LR White, and LR Gold which can be also used for Immunohistology from the same block. Cell boundaries are less obvious because less shrinkage. 

Costs: I personally believe that for renal biopsies epoxy Histotechnology is cheaper than paraffin Histotechnology. When paraffin is used HRLM and TEM must be also performed. When plastics are used, paraffin embedding is saved. It also saves Pathologist time since he only examines one set of sections for HRLM-TEM studies as compared the paraffin sections with H&E and special stains and HRLM  sampling for TEM.

Photos available in the Internet: Search for Glomerulopathies > images, in Goggle and/or Yahoo.

 
REFERENCES

1. Hoffmann EO: High Resolution Light Microscopy for the interpretation of renal biopsies. Pedriatr Nephrol (1995) 9:763-769.

2. Hoffmann EO, Rodriguez FH, Barroso E: Sub cellular light microscopy in the diagnosis of renal diseases. Patologia (1995) 28:29-38.

3. Flores TR, Hoffmann EO: Improved High Resolution Light Microscopy and Transmission Electron Microscopy Techniques in Diagnostic Pathology. J. Histotech (1997) 20:45-52.

4. Flores TR, Hoffmann EO, Velasquez M: Stat High Resolution Light Microscopy (HRLM)-Transmission Electron Microscopy (TEM) techniques for Transplant Renal Biopsies. J. Histotech (1998) 21:213-217.

 

 

Muchos saludos, Ernesto Hoffmann  and Teresa Flores.