CLED Agar is used for the differentiation and enumeration of microorganisms in urine. CLED Agar is an abbreviation for Cystine Lactose-Electrolyte-Deficient Agar. Sandys developed an electrolyte-deficient medium that prevented Proteus spp. from swarming. Mackey and Sandys modified the formula by substituting lactose and sucrose for mannitol, and increasing the amount of indicator and agar. While investigating this medium for a dip slide technique, the formula was again modified omitting sucrose and adding cystine.

CLED Agar is recommended in the spread plate technique or a dip slide for detection of bacteria in urine. This medium supports the growth of urinary pathogens and provides distinct colony morphology. CLED Agar lacks an electrolyte (salt), necessary for growth and other characteristics of certain bacteria. CLED Agar is popular in European laboratories.

Formula Liter
Enzymatic Digest of Gelatin 4 g
Enzymatic Digest of Casein 4 g
Beef Extract 3 g
Lactose 10 g
L-Cystine 0.128 g
Bromthymol Blue 0.02 g
Agar 15 g

Final pH: 7.3 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


  1. Suspend 36 g of the medium in one liter of purified water.
  2. Heat with frequent agitation and boil for one minute to completely dissolve the medium.
  3. Autoclave at 121°C for 15 minutes.

Order Details

Product # Product Description
7122A CLED Agar - 500 g
7122T CLED Agar - 5 kg