Bone Resorption Marker Test

The test measures the levels of NTx, CTx (Beta 2 crosslaps),  Acid phosphatase, and PTH in the blood. DPD in urine

• To assess the risk of fractures or bone disorders
• To assess the bone status in those receiving treatment [eg. osteoporotic patients]
• To judge response to anti-resorption or bone formation therapies in a much shorter time period than the X-ray types of bone density testing.
• In children it is mainly used to detect metabolic bone disorders like rickets, Paget’s disease, and secondary osteoporosis.

People with the following symptoms:

• Frequent bone pain
• Frequent fractures
• History of osteoporosis, Paget’s disease or any bone disorder
• Patients receiving drug therapy for bone disorders: To monitor the treatment effectiveness.

This test requires a blood sample. A tourniquet (elastic) band is placed tightly on the upper arm. The patient is then asked to make a fist. This helps in the build-up of blood filling the veins. The skin is disinfected before needle insertion and the blood sample is collected in vacutainer.  A urine sample is also collected

No special precautions required.

Acid Phosphatase (Total)

The levels may be elevated in hyperplasia of prostate, after prostatic surgery, in bone diseases like Paget`s disease, breast cancer with bone metastases, gaucher`s disease thrombocytopenia due to excessive platelet destruction.

NTx N-Tellopeptide (Collagen Crosslinked)

Elevated levels of NTx indicate increased bone resorption. Other diseases with elevated NTx are hyperparathyroidism, osteomalacia and rickets (even if not associated with hyperparathyroidism), hypercalcemia of malignancy, Paget’s disease, multiple myeloma, congenital bone diseases.

PTH

PTH shows seasonal and circadian fluctuations, with a pronounced peak in early morning and a second lower peak in the afternoon. PTH values should be interpreted in conjunction with serum calcium and phosphorus levels, and the overall clinical presentation and history of the patient. Few drugs may increase PTH levels e.g. phosphates, anti-convulsants, steroids, isoniazid, lithium and rifampin.

Beta 2 Crosslaps (B-CTx)

Elevated levels are seen in patients with increased bone resorption. Increased levels of B-CTX occur in osteoporosis, Paget’s disease, primary hyperparathyroidism, renal insufficiency and bone metastases.

A drop in CTX concentration of 35 percent to 55 percent from baseline levels after three to six months indicates effective antiresorptive therapy. The absence of a decline in CTX concentration may indicate ineffective antiresorptive therapy or lack of compliance by the patient.

DPD Deoxypyridinoline (Pyrilinks D) Urine

Elevated DPD levels indicate increased rate of bone resorption which may occur due to osteoporosis and other bone disorders.

Increased levels may also occur in post-menopausal women due to lack of estrogen activity.

• NTx N-Tellopeptide (Collagen Crosslinked) Test
• CTx (Beta 2 crosslaps) Test
• DPD Test
• Acid phosphatase Test
• PTH test

• Acid phosphatase (ACP) activity is found in prostate (richest source), bone, liver, spleen, kidney, erythrocytes and platelets.
•  ACP   is a marker for bone resorption and its level increase with increase in resorption.

• Major portion of the organic framework of bones is of type 1 collagen.
• N-telopeptide of type 1 collagen (NTx) is a specific marker of human bone resorption.

• Helps in diagnosis and differential diagnosis of hypercalcemia.
• Helps in diagnosis of hypoparathyroidism and hyperparathyroidism (primary, secondary, and tertiary).
• Helps in monitoring end-stage renal failure patients for possible renal osteodystrophy

• It is a biochemical marker of bone resorption.
• CTx is useful to assess bone resorption in patients with metabolic bone disease. It is used as an aid in monitoring antiresorptive therapies

• Deoxypyridinoline provides the structural stiffness to type 1 collagen in the bone
• DPD level in urine is useful indicator for bone resorption and thus bone disorders like osteoporosis.