DRAFT UGANDA STANDARD  
  DUS 1958 -2 
First Edition  
2018 -mm-dd 
 
 
 Reference number  
DUS 1958 -2: 2018  
© UNBS 2018   
  
Surgical sutures — Specification — Part 2: Non absorbable  
 DUS 1958 -2: 2018  
ii © UNBS 2018  – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsibl e for its correct application  
© UNBS 2018   
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Uganda  
Tel: +256 41 4 333 2 50/1/2/3  
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  DUS 1958 -2:2018  
© UNBS 2018  – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ .............................  v 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Classes of Non -absorbable sutures  ................................ ................................ ................................ .... 2 
4.1 Class I  ................................ ................................ ................................ ................................ .....................  2 
4.2 Class II  ................................ ................................ ................................ ................................ ....................  2 
4.3 Class III  ................................ ................................ ................................ ................................ ...................  2 
5 General description  ................................ ................................ ................................ ...............................  2 
6 Quality requirements ................................ ................................ ................................ .............................  2 
6.1 Identification  ................................ ................................ ................................ ................................ ..........  2 
6.2 Length  ................................ ................................ ................................ ................................ .....................  3 
6.3 Diameter  ................................ ................................ ................................ ................................ .................  4 
6.4 Tensile strength  ................................ ................................ ................................ ................................ ..... 4 
6.5 Needle attachment  ................................ ................................ ................................ ................................ . 5 
6.6 Extractable colour  ................................ ................................ ................................ ................................ . 5 
6.7 sterility  ................................ ................................ ................................ ................................ ....................  6 
7 Packaging  ................................ ................................ ................................ ................................ ...............  6 
8 Labelling  ................................ ................................ ................................ ................................ .................  6 
9 Sampling  ................................ ................................ ................................ ................................ ................  7 
Annex  A (normative)  Identification of sutures  ................................ ................................ ...............................  8 
A.1 Identification of silk  ................................ ................................ ................................ ...............................  8 
A.1.1  Method A  ................................ ................................ ................................ ................................ ................  8 
A.1.2  Method B  ................................ ................................ ................................ ................................ ................  8 
A.2 Identification of linen  ................................ ................................ ................................ ............................  8 
A.2.1  Method A  ................................ ................................ ................................ ................................ ................  8 
A.2.2  Method B  ................................ ................................ ................................ ................................ ................  8 
A.3 Identification of poly (ethyleneterephthalate)  ................................ ................................ ....................  8 
A.3.1  Method A  ................................ ................................ ................................ ................................ ................  8 
A.3.2  Method B  ................................ ................................ ................................ ................................ ................  8 
A.4 Identification of polyamide -6 ................................ ................................ ................................ ................  8 
A.4.1  Method A.  ................................ ................................ ................................ ................................ ...............  9 
A.4.2  Method B.  ................................ ................................ ................................ ................................ ...............  9 
A.5 Identification of polyamide -6/6 ................................ ................................ ................................ .............  9 
A.5.1  Method A  ................................ ................................ ................................ ................................ ................  9 
A.5.2  Method B.  ................................ ................................ ................................ ................................ ...............  9 
A.5.3  Method C  ................................ ................................ ................................ ................................ ................  9 
A.5.4  method D  ................................ ................................ ................................ ................................ ................  9 
A.6 Identification of polypropylene  ................................ ................................ ................................ ............  9 
A.6.1  Method A.  ................................ ................................ ................................ ................................ ...............  9 
A.6.2  Method B.  ................................ ................................ ................................ ................................ ...............  9 
A.6.3  Method C.  ................................ ................................ ................................ ................................ ...............  9 
A.7 Identification of stainless steel  ................................ ................................ ................................ ..........  10 
A.8 Identification of poly (vinylidene difluoride)  ................................ ................................ .....................  10 
A.8.1  Method A  ................................ ................................ ................................ ................................ ..............  10 
A.8.2  Method B  ................................ ................................ ................................ ................................ ..............  10 
A.8.3  Method C  ................................ ................................ ................................ ................................ ..............  10 DUS 1958 -2: 2018  
iv © UNBS 2018  – All rights reserved  
 Annex  B (normative)  Diameter of sutures  ................................ ................................ ................................ .... 11 
Annex  C (normative)  Tensile strength  ................................ ................................ ................................ ..........  12 
Annex  D (normative)  Needle attachment ................................ ................................ ................................ ...... 13 
Annex  E (normative)  Extr actable colours  ................................ ................................ ................................ .... 14 
Annex F (normative )  Sterility test  ................................ ................................ ................................ ................  15 
F1 Introduction  ................................ ................................ ................................ ................................ .........  15 
F.2 Fluid thioglycollate medium  ................................ ................................ ................................ ..............  15 
F.3 Alternative thioglycollate medium  ................................ ................................ ................................ .... 16 
F.4 Soya -bean casein digest medium  ................................ ................................ ................................ ..... 16 
F.5 Sterility  ................................ ................................ ................................ ................................ .................  16 
Bibliography  ................................ ................................ ................................ ................................ .....................  17 
 DUS 1958 -2:2018  
© UNBS 2018  – All rights reserved  v 
 Foreword  
Uganda National Bureau of Standards (UNBS) is a paras tatal under the Ministry of Trade , Industry and 
Cooperatives established under Cap 327 , of the Laws of Uganda , as amended .  UNBS is mandated to co -
ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO ) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT  Agreement  of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committe es. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other interested parties.  
Draft Uganda Standards adopted by t he Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
The committee responsible for this document is Technical Committee UNBS /TC 14, Medical devices.  
US 1958  consists of the following parts, under the Surgical sutures — Specification  
  Part 1: Surgical sutures — Specification — Part 1: Absorbable   
  Part 2 : Surgical sutures — Specification — Part 2: Non Absorbable  DUS 1958 -2: 2018  
vi © UNBS 2018  – All rights reserved  
 Introduction  
Surgical s utures are used in a variety of different surgical procedures to close wounds and aid in tissue 
healing.  These sutures may be a single filament or multifilament or braided or twisted with or without a coating  
Surgical sutures are classified into two types:  
a) Absorbable surgical sutures  
b) Non-absorbable surgical sutures  
 DRAFT UGANDA STANDARD  DUS 1958 -2: 2018  
 
© UNBS 2018 – All rights reserved  1 
 Surgical sutures  — Specification  — Part 2: Non absorbable  
1 Scope   
This D raft Uganda Standard specifie s the requirements , sampling and test methods for non absorbable  
surgical sutures  
2 Normative references   
The following referenced documents referred to in the text in such a way that some or all of their content 
constitutes requirements of this document. For dat ed references, only the edition cited applies. For undated 
references, the latest edition of the referenced document (including any amendments) applies.  
WDUS ISO 5832 -1, Implants for surgery -- Metallic materials -- Part 1: Wrought stainless steel  
US ISO 2 4153 —.Random sampling and randomisation procedures  
3 Terms and definitions   
For the purposes of this document, the following terms and definitions apply.  
ISO and IEC maintain terminological databases for use in standardization at the following addresses:   
— ISO Online browsing platform: available at http://www.iso.org/obp  
3.1 
monofilament  
suture  made of a single strand . 
3.2  
multifilament  
suture composed of several filaments twisted or braided together.  
3.3  
non-absorbable sutures  
sutures which, when intr oduced into a living  tissue , are not metabolised by that tissue . 
3.4 
surgical sutures  
flexible strands prepared from collagen derived from heathy animals or from synthetic polymer  DUS 1958 -2:2018  
2 © UNBS 2018  – All rights reserved  
 4 Classes of Non-absorbable sutures  
4.1 Class I  
These are composed of silk or synthetic fibres of monofilament, twisted or braided construction where the 
coating if any does not significantly affect the thickness  
4.2 Class II  
These are composed of cotton or linen fibres or coated natural or synthetic fibres where coating signifi cantly 
affects the thickness but does not contribute to the strength.  
4.3 Class III  
These are composed of monofilament or multifilament metal wire.  
5 General description  
5.1 The suture shall either be monofilament or multifilament. If multifilament, the in dividual filament may be 
combined by spinning, twisting, braiding or any combination.  
5.2 It shall be sterile . 
5.3 It may be coloured , coated  or both  
6 Quality requirements  
6.1 Identification  
The sutures shall comply with the requirements given in table 1 when tested in accordance with annex A. DUS 1958 -2: 2018  
© UNBS 2018  – All rights reserved  3 
 Table 1 — Identification of non -absorbable suture materials.  
Material  Requirements  Test method.(Annex A)  
Silk a cross -section is more or less triangular to semi -circular, 
with rounded edges and without a lumen  A.1.1 
The fibres shall be coloured pale yellow  A.1 2  
Linen  The fibres are seen to be 12 µm to 31 µm wide and, along 
the greater part of their length, have thick walls, sometimes 
marked with fine longitudinal striations, and a narrow 
lumen. The fibres gradu ally narrow to a long, fine point. 
Sometimes there are unilateral swellings with transverse 
lines.  A.2 1 
The fibres are coloured violet -blue A.2.2  
Polyethylene  terephthalate  
(PET)  Dissolves with difficulty  A.3.1 
The material remains intact even after  immersion for 6 h  A.3.2 
Polyamide -6 No crystals appear  A.4.1 
Dissolves  A.4.2 
Polyamide -6/6 It melts and burns forming a hard globule of residue with off 
characteristic odour resembling that of celery  A.5.1 
A violet -brown colour slowly appears on th e paper and 
fades slowly in air; it disappears almost immediately on 
washing with dilute sulfuric acid R  A.5.2 
The material disintegrates in the cold and dissolves within a 
few minutes.  A.5.3 
Does not dissolve in 20 ml of a 70 per cent m/m solution of 
anhydrous formic acid R but dissolves in 20 ml of an 80 per 
cent m/m solution of anhydrous formic acid R  A.5.4 
Polypropylene  It burns with a blue flame giving off an odour of burning 
paraffin wax and of octyl alcohol.  A.6.1 
Complies when compared  with t he spectrum obtained with 
polypropylene CRS  A.6.2  
The relative density of the material s hall be  0.89 g/ml to 
0.91 g/m l A.6.3  
Stainless steel  Comply with the requirements of 4.2 table1 of WDUS ISO 
5832 -1  A.7  
Poly (vinylidene difluoride)  It melts in a flame and does not burn after removal of the 
flame . 
No green colour is produced  when heated with an oxidizing 
flame.  A.8.1  
The spectrum shall show absorption maxima at the 
following wave -numbers: 838.3 ± 0.5 cm -1, 873.3 ± 1 cm -1, 
1070.0 ± 2 cm -1, 1165.0 ± 10 cm -1, 1275 ± 0.5 cm -1, 1399 
± 5 cm -1. A.8.2  
The relative density of the material is 1.71 to 1.78.  A.8.3  
 
6.2 Length  
The length of the suture without stretching shall be not less than 95 per cent of the length stated on the label 
and shall not excee d 400 cm .  DUS 1958 -2:2018  
4 © UNBS 2018  – All rights reserved  
 6.3 Diameter  
The diameter of sutures shall comply with requirements given in Table 2 when d etermined using a suitable 
mechanical instrument capable of measuring with an accuracy of at least 0.002 mm and having a circular 
pressor foot 10 -15 mm in  diameter  as prescribed in annex B . 
Table 2 — Average knot -pull limits and diameters of non absorbable sutures  
Metric Size 
(gauge no.)  Limits on Average 
Diameter (mm)  Limits on Average Knot -Pull 
(except where otherwise  
specified)a Tensile Strength (in kgf)b Limits on Average Knot -Pull 
(except where otherwise  
specified)a Tensile Strength (in N)b 
Min. Max.  Class I ,Min. Class II, Min. Class III, Min. Class I, Min. Class  II, 
Min. Class III, 
Min. 
0.01 0.001  0.009  0.001a — 0.002a 0.01a — 0.02a 
0.1 0.010  0.019  0.006a 0.005a 0.02a 0.06a 0.05a 0.20a 
0.2 0.020  0.029  0.019a 0.014a 0.06a 0.194a 0.14a 0.59a 
0.3 0.030  0.039  0.043a 0.029a 0.07a 0.424a 0.28a 0.68a 
0.4 0.040  0.049  0.06 0.04 0.11 0.59 0.39 1.08 
0.5 0.050  0.069  0.11 0.06 0.16 1.08 0.59 1.57 
0.7 0.070  0.099  0.20 0.11 0.27 1.96 1.08 2.65 
1 0.10 0.149  0.40 0.23 0.54 3.92 2.26 5.30 
1.5 0.15 0.199  0.60 0.46 0.82 5.88 4.51 8.04 
2 0.20 0.249  0.96 0.66 1.36 9.41 6.47 13.3 
3 0.30 0.339  1.44 1.02 1.80 14.1 10.0 17.6 
3.5 0.35 0.399  2.16 1.45 3.40a 21.2 14.2 33.3a 
4 0.40 0.499  2.72 1.81 4.76a 26.7 17.8 46.7a 
5 0.50 0.599  3.52 2.54 5.90a 34.5 24.9 57.8a 
6 0.60 0.699  4.88 3.68 9.11a 47.8 36.1 89.3a 
7 0.70 0.799  6.16 — 11.4a 60.4 — 112a 
8 0.80 0.899  7.28 — 13.6a 71.4 — 133a 
9 0.90 0.999  9.04 — 15.9a 88.6 — 156a 
10 1.00 1.099  — — 18.2a — — 178a 
11 1.100  1.199  — — 20.5a — — 201a 
12 1.200  1.299  — — 22.8a — — 224a 
a The tensile strength of sizes smaller than metric size 0.4 is measured by straight pull.  The tensile strength of sizes larger 
than metric size 3 of monofilament Class III (metallic). Non absorbable Surgical Suture is measured by straight pull. Silver 
wire meets the tensile strength values of Class I Sutures but is tested in the same manner as  Class III Sutures.  
 
6.4 Tensile  strength  
The tensile strength of sutures shall comply with the requirements in Table  2 when tested  in accordance with 
annex C  DUS 1958 -2: 2018  
© UNBS 2018  – All rights reserved  5 
 6.5 Needle attachment  
6.5.1  If the sutures are supplied with an eyeless needle attached that is  not stated to be detachable, they 
shall comply with  the requirements given in table 3 when tested in accordance with in annex D . 
Table 3 — Needle Attachment for Non-absorbable  sutures  
Gauge Number  Limits on Needle Attachment  
Non absorbable 
Sutures  Average  (in 
kgf) (Min.)  Individual (in  
kgf) (Min.)  Average (in N)  
(Min.)  Individual (in N)  
(Min.)  
0.1 0.007  0.005  0.069  0.049  
0.2 0.014  0.010  0.137  0.098  
0.3 0.021  0.015  0.206  0.147  
0.4  0.050  0.025  0.490  0.245  
0.5 0.080  0.040  0.784  0.392  
0.7 0.17 0.08 1.67 0.784  
1 0.23  0.11 2.25 1.08 
1.5 0.45 0.23 4.41 2.25 
2 0.68  0.34 6.67 3.33 
3 1.10  0.45 10.8 4.41 
3.5 1.50 0.45 14.7 4.41 
4 1.80  0.60 17.6 5.88 
5 and larger  1.80 0.70 17.6 6.86 
 
6.5.2  If sutures are supplied with removable needle, they shall com ply with the requirements given in table 
4 when tested in accordance with annex  D 
Table 4 — Removable Needle Attachment for non-absorbable sutures  
Gauge Number  Limits on Needle Attachment  
Non absorbable 
Sutures  minimum (in kgf)  Maximum (in kgf)  Minimum (i n N) Maximum (in N)  
1 0.028  1.59 0.274  15.6 
1.5 0.028  1.59 0.274  15.6 
2 0.028  1.59 0.274  15.6 
3 0.028  1.59 0.274  15.6 
3.5 0.028  1.59 0.274  15.6 
4 0.028  1.59 0.274  15.6 
5 0.028  1.59 0.274  15.6 
 
6.6 Extractable colour  
Dyed sutures  shall be colour  fast when  tested in accordance with Annex E.  DUS 1958 -2:2018  
6 © UNBS 2018  – All rights reserved  
 6.7 sterility  
It shall be sterile when  tested in accordance with annex F  
7 Pack aging 
7.1 The non -sterile suture shall be packaged in suitable well closed sachet or packets or containers.  
7.2 The sterile sutures  (dry or in fluid) shall be packed in sachets or packets or containers that maintain 
sterility until the container is opened and allows the withdrawal and use of the suture in aseptic conditions.  
7.3 A number of sachets (packets or containers) may be packa ged in a box . 
8 Labelling  
8.1 The primary package of the suture shall be legibly  and indelibly  marked with the following information:  
a) Name and address of manufacturer;  
b) name of the product,  
c) material of the suture;  
d) size of the suture   
e) gauge number;  
f) structur e (monofilament  or multifilament ); 
g) length of suture, in centimetres ; 
h) sterile  
i) if appropriate, that the suture is coloured,  
j) batch number;  
k) kind of needle if included;  
l) number of sutures if multiple;  
m) Warnings, like “DO NOT RESTERILIZE. DISCARD OPEN UNUSED SUTURE S. STORE AT ROOM 
TEMPERATURE. AVOID PROLONGED EXPOSURE TO ELEVATED TEMPERATURES ”; and  
n) date of manufacture and expiry . 
8.2 If the sachets (packets or containers) are packaged in boxes, the boxes shall be labelle d with the 
following  
i) name and address of the  manufacturer/ packer/distributor;  
ii) composition of any packaging fluid if used;  
iii) batch number;  
iv) name of product;  DUS 1958 -2: 2018  
© UNBS 2018  – All rights reserved  7 
 v) whether sterile  
Note — if the suture is packaged with a fluid, make sure that testing is done within 2 minutes after removing it from the 
fluid.  
9 Sampling  
Sampling shall be done in accordance with US ISO 24153.  DUS 1958 -2:2018  
8 © UNBS 2018  – All rights reserved  
 Annex  A 
(normative)  
 
Identification of sutures  
A.1 Identification of silk  
A.1.1  Method A  
Dissect the end of a suture, using a needle or fine tweezers, to isolate a few individual fibres. T he fibres are 
sometimes marked with very fine longitudinal striations parallel to the axis of the suture. Examined under a 
microscope . 
A.1.2  Method B  
Impregnate isolated fibres with iodinated potassium iodide solution R.  
A.2 Identification of linen  
A.2.1  Method A  
Dissect the end of a suture, using a needle or fine tweezers, to isolate a few individual fibres. Examined under 
a microscope  
A.2.2  Method B  
Impregnate isolated fibres with iodinated zinc chloride solution R. 
A.3 Identification of poly (ethylene terephthalate)  
It is practically insoluble in most of the usual organic solvents, but is attacked by strong alkaline solutions. It is 
incompatible with phenols.  
A.3.1  Method A  
Heat  50 mg in 50 m l of dimethylformamide R.  
A.3.2  Method B  
To about 50 mg add 10 ml  of hydrochloric acid R1 . 
A.4 Identification of polyamide -6  
It is practically insoluble in the usual organic solvents; it is not attacked by dilute alkaline solutions (for 
example a 100 g/ l solution of sodium hydroxide R) but is attacked by dilute mi neral acids (for example a 20 g/ l 
solution of sulfuric acid R), by hot glacial acetic acid R and by a 70 per cent m/m solution of anhydrous formic 
acid R.  DUS 1958 -2: 2018  
© UNBS 2018  – All rights reserved  9 
 A.4.1 Method A.  
Heat about 50 mg with 0.5 mL of hydrochloric acid R1 in a sealed glass tube at 110 ° C for 18 h and allow to 
stand for 6 h .  
A.4.2 Method B.  
Dissolve 50 mg in 20 mL of a 70 per cent m/m solution of anhydrous formic acid R.  
A.5 Identification of polyamide -6/6  
It is practically insoluble in the usual organic solvents; it is not attacked by dilute alkaline solutions (for 
example a 100 g/ l solution of sodium hydroxide R) but is attacked by dilute mineral acids (for example a 20 g/ l 
solution of sulfuric acid R), by hot glacial acetic acid R and by an 80 per cent m/m solution of anhydrous 
formic  acid R.  
A.5.1 Method A  
In contact with a flame .  
A.5.2 Method B.  
Place about 50 mg in an ignition tube held vertically and heat gently until thick fumes are evolved. When the 
fumes fill the tube, withdraw it from the flame and insert a strip of nitrobenz aldehyde paper R.  
A.5.3 Method C  
To about 50 mg add 10 m l of hydrochloric acid R1.  
A.5.4 method D  
Dissolve 50 mg of sample  in 20 m l of a 70 per cent m/m solution of anhydrous formic acid R and also  in 20 m l 
of an 80 per cent m/m solution of anhydrous for mic acid R.  
A.6 Identification of polypropylene  
Polypropylene is soluble in decahydronaphthalene, 1 -chloronaphthalene and trichloroethylene. It is not soluble 
in alcohol, in ether and in cyclohexanone.   
A.6.1 Method A.  
It softens at temperatures between 1 60 °C and 170 °C.  
A.6.2 Method B.  
To 0.25 g add 10 m l of toluene R  and boil under a reflux condenser for about 15 min. Place a few drops of the 
solution on a disc of sodium chloride R  slide and evaporate the solvent in an oven at 80 °C. Examine by 
infrare d absorption spectrophoto metry.  
A.6.3 Method C. 
To 2 g add 100 m l of water R  and boil under a reflux condenser for 2 h. Allow to cool. Determi ne the relative 
density of the material  using a hydrostatic balance.  DUS 1958 -2:2018  
10 © UNBS 2018  – All rights reserved  
 A.7 Identification of stainless steel   
Stainl ess steel sutures shall be identified in accordance with ISO 5832 - 1.  
A.8 Identification of poly (vinylidene difluoride)   
It is soluble in warm dimethylformamide. It is insoluble in ethanol, hot and cold isopropyl alcohol, ethyl acetate, 
tetrachlorethyle ne.  
A.8.1 Method A  
A.8.1.1 Melts the  strand between 170 °C and 180 °C.  
A.8.1.2 Place a small piece of suture on an annealed copper wire or sheet. Heat in an oxidising flame.  
A.8.2 Method B  
Dissolve 0.25 g of the suture in 10 m l of dimethylformamide R  and boil under a reflux condenser for about 15 
min. Place a few drops of the solution on a sodium chloride R  slide and evaporate the solvent in an oven at 80 
°C (1 h). Examine by infrare d absorption spectrophotometry.  
A.8.3 Method C  
To 2 g of suture add 100 m l of water R  and boil under a reflux condenser for 2 h. Allow to cool. Determine the 
relative density.  DUS 1958 -2: 2018  
© UNBS 2018  – All rights reserved  11 
 Annex  B 
(normative)  
 
Diameter of sutures  
B.1 Lay the strand across the center of the anvil and presser foot and gently lower the foot until its entire 
weight rests upon the suture Measure non -absorbable sutures whether packaged in dry form or in fluid 
immediately after removal from the container without drying or conditioning.  
B.2 Measure the diameter of th e suture at three points corresponding roughly to one -fourth, one half and 
three fourths of its length.  (See Table 2) 
B.3 In case of braided sutures of size larger than  3-0 (metric size) make two measurements at each end 
point at right angles to each other  and use the average as observed diameter at that point.  
B.4 In case of multifilament sutures, attach a portion of the designated section of the strand in affixed clamp 
in such a way that the strand lies across the centre of anvil. While holding the strand  in the same plane as the 
surface of the anvil, place under tension by suitable means such as by passing the free end of the strand 
around a cylinder or pulley and attaching to the free end a weight of about one half of the knot pull limit.  DUS 1958 -2:2018  
12 © UNBS 2018  – All rights reserved  
 Annex  C 
(norma tive) 
 
Tensile strength  
C.1 The minimum breaking load is determined over a simple knot formed by placing one  end of a suture 
held in the right hand over the other end held in the left hand,  passing one en d over the suture and through 
the loop so formed (see Figure C1) and pulling the knot tight.  
 
Figure C1 — Simple knot  
C.1.1 Determine the tensile strength of surgical suture on a motor -driven tensile strength testing machine 
having suitable clamps for ho lding the specimen firmly and using either the principle of constant rate of load 
on specimen or the principle of constant rate of elongation of specimen, as described below.  
C.1.2 Gauge length is defined as the interior distance between the two clamps. F or gauge lengths of 125 to 
200 mm, the mobile clamp is driven at a constant rate of elongation of 30 ± 5 cm per minute. For gauge 
lengths of less than 125 mm, the rate of elongation per minute is adjusted to equal 2 times the gauge length 
per minute. For e xample, a 5 -cm gauge length has a rate of elongation of 10 cm per minute.  
C.1.3 Determine the tensile strength of the suture, whether packaged in dry form or in fluid, promptly after 
removal from the container, without prior drying or conditioning.  
C.1.4 Attach one end of the suture to the clamp at the load end of the machine, pass the other end through 
the opposite clamp, applying sufficient tension so that the specimen is taut between the clamps, and engage 
the second clamp. Perform as many breaks as are  specified in the individual monograph. If the break occurs 
at the clamp, discard the reading on the specimen . DUS 1958 -2: 2018  
© UNBS 2018  – All rights reserved  13 
 Annex  D 
(normative)  
 
Needle attachment  
D.1 If the sutures are supplied with an eyeless needle a ttached that is not stated to be detachable, they 
comply with  the test for needle attachment shown in table 3 and  for removable needle attachment, they shall 
comply with the table 4 . 
D.2 Carry out the test on 5 sutures. Use a suitable tensilometer, such as  that described for the 
determination of the minimum breaking load.  
D.3 Fix the needle and suture (without knot) in the clamps of the apparatus in such a way that the swaged 
part of the needle is completely free of the clamp and in line with the direction  of pull on the suture.  
D.4 Set the mobile clamp in motion and note the force required to break the suture or to detach it from the 
needle.  
D.5 The average of the 5 determinations and all individual values are not less than the respective values 
given in  Table 3  and Table 4  for the gauge number concerned.  
D.6 If not more than 1 individual value fails to meet the individual requirement, repeat the test on an 
additional 10 sutures. The attachment complies with the test if none of these 10 values is less tha n the 
individual value in Table 3  and Table 4 for the gauge number concerned . 
 DUS 1958 -2:2018  
14 © UNBS 2018  – All rights reserved  
 Annex  E 
(normative)  
 
Extractable colours  
E.1 Place 0.25 g of the suture to be examined in a conical flask, add 25.0 m l of water  R and cover the 
mouth of the flask with a short -stemmed funnel.  
E.2 Boil for 15 min, cool and adjust to the  original volume with water R.  
E.3 Depending on the colour of the suture, prepare the appropriate reference solution as described in Table  
E1 using the primary colour solutions. The test solution shall not be more intensely coloured than the 
appropriate reference solution . 
Table E1 – Colour referencing solution.  
 DUS 1958 -2: 2018  
© UNBS 2018  – All rights reserved  15 
 Annex F  
(normative )  
 
Sterility test  
F1 Introduction  
The following culture media have b een found to be suitable for the test for sterility.  Fluid thioglycollate 
medium is primarily intended for the culture of anaerobic bacteria; however, it will also detect aerobic bacteria. 
Soya -bean casein digest medium is suitable for the culture of both  fungi and aerobic bacteria.  
F.2 Fluid thioglycollate medium  
L-Cystine                     0.5 g   
Agar                      0.75 g  
Sodium chloride                    2.5 g  
Glucose monohydrate/anhydrous               5.5 g/5.0 g  
Yeast extract (water -soluble)                 5.0 g  
Pancreatic digest of casein                  15.0 g  
Sodium thioglycollate or                  0.5 g  
Thioglycollic acid                    0.3 m l 
Resazurin sodium solution (1g/L of resazurin sodium), freshly prepared        1.0 m l 
Water R                      1000 m l 
pH after sterilisation 7.1 ± 0.2  
F.2.1  Mix the L -cystine, agar, sodium chloride, glucose, water -soluble yeast extract and pancreatic  digest of 
casein with the water R and heat until solution is effected .  
F.2.2  Dissolve the sodium  thioglycollate or thioglycollic acid in the solution and, if necessary , add 1 M 
sodium hydroxide so that, after sterilisation, the solution will have  a pH of 7.1 ± 0.2. If filtration is necessary, 
heat the solution again without boiling  and filter while h ot through moistened filter paper.  
F.2.3  Add the resazurin sodium  solution, mix and place the medium in suitable vessels which provide a 
ratio of  surface to depth of medium such that not more than the upper half of the medium  has undergone a 
colour chan ge indicative of oxygen uptake at the end of the  incubation period. Sterilise using a validated 
process. If the medium is stored , store  at a temperature between 2 °C and 25 °C in a sterile, airtight container.  
F.2.4  If more  than the upper one -third of th e medium has acquired a pink colour, the medium  may be 
restored once by heating the containers in a water -bath or in free - flowing steam until the pink colour 
disappears and cooling quickly, taking care to prevent  the introduction of non -sterile air into t he container. Do 
not use the medium for  a longer storage period than has been validated.Fluid thioglycollate medium is to be 
incubated at 30 °C - 35 °C.  DUS 1958 -2:2018  
16 © UNBS 2018  – All rights reserved  
 F.2.5  For products containing a mercurial preservative that cannot be tested by the membrane -filtration  
method, fluid thioglycollate medium incubated at 20 °C - 25 °C may be  used instead of soya -bean casein 
digest medium provided that it has been validated  as described in growth promotion test.  
F.3 Alternative thioglycollate medium  
Where prescribed or justi fied and authorised, the following alternative thioglycollate medium may be used. 
Prepare a mixture having the same composition as that of the fluid thioglycollate medium, but omitting the 
agar and the resazurin sodium solution, sterilise as directed above . The pH after sterilisation is 7.1 ± 0.2. Heat 
in a water -bath prior to use and incubate at 30  °C - 35 °C under anaerobic conditions.  
F.4 Soya -bean casein digest medium  
Pancreatic digest of casein                  17.0 g  
Papaic digest of soya -bean meal                3.0 g  
Sodium chloride                    5.0 g  
Dipotassium hydrogen phosphate                2.5 g  
Glucose monohydrate/anhydrous               2.5 g/2.3 g  
Water R                      1000 m l 
pH after sterilization  7.3 ± 0.2  
F.4.1 Dissolve the solid s in water R , warming slightly to effect solution. Cool the solution to  room 
temperature. Add 1 M sodium hydroxide , if necessary, so that after sterilisation  the solution will have a pH of 
7.3 ± 0.2.  
F.4.2 Filter, if necessary, to clarify , distribute  into suitable vessels and sterilise using a validated process. 
Store at a temperature  between 2 °C and 25 °C in a sterile well -closed container, unless it is intended  for 
immediate use. Do not use the medium for a longer storage period than  has been validated. Soya -bean 
casein digest medium is to be incubated at 20 °C - 25 °C .  
The media used comply with the following tests, carried out before or in parallel with  the test on the product to 
be examined.   
F.5 Sterility  
Incubate portions of the media for 14 days. No  growth of micro -organisms occurs.   DUS 1958 -2: 2018  
© UNBS 2018  – All rights reserved  17 
 Bibliography  
[1] British Pharmacopoeia, 2017 , published by The Stationery Office on behalf of the Medicines and 
Healthcare Products Regulatory Agency  
[2] ISO 11135 (both parts), Sterilization of health care products — Ethylene oxide  
[3] ISO 11137 (all parts), Sterilization of health care products — Radiation  
[4] ISO 17665 (all parts), Sterilization of health care products — Moist heat  
[5] US Pharmacopoeia  40 
  
18 © UNBS 2018  – All rights reserved  
 Certification marking  
Products that conform to Uganda standard s may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those  licensed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply  with the 
requirements of that standard under a system of supervision, control and testing in accordance with the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to t hat standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 DUS 1958 -2: 2018    
 
ICS 11.040.30  
Price based on nn pages  
© UNBS  2018– All rights reserved