BDS 1st Year Biochemistry Notes for Quick Revision

BDS 1st Year Biochemistry practicals include several blood collection tubes, urine tests, reagents, and laboratory instruments. Each has a specific use, principle, or observation that you need to remember for practical classes and viva preparation. With so many topics to revise, it can be difficult to recall these details quickly before an examination.

These notes bring the important practical points together in one place. You can use them to revise the contents and uses of blood collection tubes, urine tests, reagents, and laboratory equipment in a simple and organised manner. 

BDS 1st Year Biochemistry Notes

These notes provide a concise overview of important Biochemistry practical topics for BDS 1st Year students. They cover common laboratory instruments, reagents, blood collection tubes, urine tests, principles, uses, and observations for quick revision. 

1. The Plain Bulb (Red Cap)

Also called: Plain Vacutainer or Red Cap Tube

Contains: No anticoagulant (Plain)

The plain Vacutainer is used for maximum analyte estimations in biochemistry.

Use: Collection of blood samples for biochemical estimations:

• Urea estimation

• Creatinine estimation

• Enzyme assays: SGOT, SGPT

Department: Biochemistry

2. The Fluoride Bulb (Grey Cap)

Contains: Sodium fluoride + Potassium oxalate (1:3 ratio)

Function: Fluoride inhibits enolase, a glycolysis enzyme. It prevents glucose breakdown and maintains the true glucose value when there is a lag between sample collection and estimation.

Use: For blood glucose estimation when there is a delay between collection and analysis.

3. The EDTA Tube (Purple Cap)

Contains: Ethylenediaminetetraacetic Acid (EDTA)

Use: For haematological tests, including Complete Blood Count (CBC).

Department: Pathology

4. Urine Dipstick (Multistix)

Description: Color-coded urine test strip with multiple reagent pads.

Use: Detection of abnormal components in urine, including:

• Glucose

• Protein

• Ketone bodies

• Bilirubin

• Urobilinogen

• Nitrite

The urine dipstick has replaced older manual tests like Benedict's, Rothera's, and Heat Coagulation Tests. Its interpretation is based on the color coding of reagent pads.

5. H₂S (Sulphur) Test

Principle: Detects bile salts in urine.

Reagent: Sulphur powder.

Positive test: Sulphur sinks to the bottom. Bile salts are present.

Negative test: Sulphur floats on the surface. Bile salts are absent.

Seen in: Obstructive and hepatocellular jaundice.

Control tube: Shows floating sulphur powder.

6. Dropper

Use: Used for adding precise drops of urine or reagents in tests such as Benedict's test.

Example: 8 drops of urine + 5 mL Benedict's reagent → for semi-quantitative glucose estimation.

7. Micropipette (Fixed Volume – 1000 µL = 1 mL)

Use: Used for quantitative biochemical estimations.

Features: Two resistances:

1. 1st stop: For aspiration

2. 2nd stop: For complete delivery

Press till the first resistance for aspiration and press completely for dispensing.

8. Variable Volume Micropipette (5–50 µL)

Use: Used for taking small volumes of samples, such as 10–20 µL.

Common in: Automated/ELISA setups and precise biochemical assays.

9. Heat Coagulation Test

Principle: Protein denaturation by heat.

Observation: Coagulum in the upper part indicates a positive test and shows that protein is present.

Control: Lower part unheated.

The upper heated part shows coagulum, while the lower unheated part acts as control in the same tube.

Used for: Detection of albumin/protein in urine.

10. Test Tube Rack

Use: Holds multiple test tubes upright during experiments and incubation.

Skill Module Notes: Biochemistry.

10A. Test Tube Holder

Description: Hand-held metallic or wooden clamp used to hold a single test tube.

Use:

• Used to hold a test tube during heating.

• Used while handling corrosive reagents, such as nitric acid and sulphuric acid.

11. Spatula

Use: Used to pick solid reagents or powders.

Example: Sulphur for H₂S test.

12. Benedict's Reagent

Benedict's reagent is a blue-colored solution containing copper sulphate, sodium citrate, and sodium carbonate.

Description: Blue-colored chemical reagent used for detection of reducing sugars in urine.

Composition:

• Sodium citrate

• Sodium carbonate

• Copper sulphate

Use: Used in Benedict's test for qualitative and semi-quantitative detection of reducing sugars in urine.

Principle: Reducing sugars reduce cupric ions (Cu²⁺) to cuprous oxide (Cu₂O), producing a colored precipitate.

Viva Note: Brick-red precipitate indicates high concentration of reducing sugar (>2 g%).

Benedict's Test Results: Color variations occur from a blue solution to a green/yellow precipitate, orange-red precipitate, and brick-red precipitate.

13. Sulfosalicylic Acid Test

Use: Detection of protein/albumin in urine.

Procedure: 3 mL urine + 3–4 drops of sulfosalicylic acid.

Observation: White turbidity indicates that protein is present.

14. Beaker

Use: Used for mixing and transferring reagents.

15. Sulphur Powder

Use: Used in H₂S test for bile salt detection.

Positive: Sulphur sinks down.

Seen in: Obstructive/hepatocellular jaundice.

16. Acetic Acid (1%)

Use: Used in the heat coagulation test to differentiate protein from phosphate.

Protein: Coagulum persists/intensifies.

Phosphate: Coagulum disappears.

17. Urinometer & Measuring Cylinder (50 mL)

Use: Measures specific gravity of urine.

Normal range: 1.010–1.025

Increased in:

• Concentrated urine

• Glycosuria (Diabetes mellitus)

Decreased in:

• Dilute urine

• Diabetes insipidus

18. Picric Acid

Use: Used in Jaffe's test for creatinine estimation.

It is also used in various other biochemical investigations.

Principle: Formation of orange-red creatinine picrate complex.

19. Digital Photo Colorimeter

Principle: Based on Beer–Lambert's law.

Use: Measures Optical Density (OD) of colored solution.

Applications:

• Glucose

• Urea

• Creatinine

• Bilirubin estimations

20. Centrifuge Machine

Use: Separation of serum from cells after clotting.

Speed control: Adjustable, rpm-based.

Slots: Usually 8 for test tubes.

21. Incubator

Temperature: Maintained at 37°C.

Use: Used for incubation of test tubes for a fixed time during biochemical reactions.

Primary use: Incubation of biochemical reactions for enzyme assays.

22. Hot Air Oven

Use: Dry sterilization of glassware and instruments.

23. Semi-Automated Analyzer

Use: Used for quantitative biochemical estimations.

Features: Covers UV spectrum and is suitable for enzyme assays such as SGOT and SGPT.

24. Spectrophotometer

Principle: Measures absorbance over a broad UV-visible range.

Use:

• Enzyme kinetics

• Bilirubin estimation

• Protein estimation

• Creatinine estimation

25. Electrophoresis Apparatus

Principle: Separation of charged particles under electric field.

Used for diagnosis of:

• Multiple myeloma

• Cirrhosis of liver

• Sickle cell anemia

• Thalassemia

26. Digital pH Meter

Use: Measures pH of solutions accurately using electrode probe.

Application:

• Buffers

• Biochemical experiments

• Enzyme assays

The BDS 1st Year Biochemistry Notes cover the listed blood collection tubes, urine testing methods, reagents, laboratory equipment, and biochemical instruments.

For quick practical revision, focus on the contents and uses of blood collection tubes, the principles and observations of urine tests, and the uses of laboratory instruments.

These BDS 1st Year Biochemistry Notes provide the listed practical information in a structured format for revision.

The BDS 1st Year Biochemistry Notes can be used to revise the important practical points before Biochemistry laboratory sessions and practical examinations.